DIAGNOSIS AND TESTING

412-00-1 Climate Control System - General Information 412-00-1 DIAGNOSIS AND TESTING Climate Control System Refer to Wiring Diagrams Cell 54, Air Conditioning/Heater for schematic and connector information. Special Tool(s) Worldwide Diagnostic System (WDS) 418-F224, New Generation STAR (NGS) Tester 418-F052, or equivalent scan tool Rotunda 73 III Multimeter 105-R0057 or equivalent Special Tool(s) Pressure Test Kit 014-R1072 or equivalent Connector, Refrigerant Pressure Line 412-093 (T94P-19623-E) Vacuum Pump Kit 416-D002 (D95L-7559-A) or equivalent R-134a Manifold Gauge Set 176-R032A or equivalent Set, A/C Fittings 412-DS028 (014-00333, D93L-19703-B) or equivalent Refrigerant Leak Detector 216-00001 or equivalent Copyright 2003, Ford Motor Company Last updated: 1/30/2007

412-00-2 Climate Control System - General Information 412-00-2 DIAGNOSIS AND TESTING Vacuum Schematic

412-00-3 Climate Control System - General Information 412-00-3 DIAGNOSIS AND TESTING Item Part Number Description Item Part Number Description 1 Vacuum to the auxiliary A/C system (if equipped) 2 18A318 Vacuum control motor floor/panel door 3 Panel vent airflow 4 Floor/panel door (full vacuum position) (part of 18471) 5 18B545 Temperature blend door (full heat position) 6 19860 Evaporator core 7 19A813 Air inlet door (full vacuum position) 8 Outside air inlet 9 18A318 Vacuum control motor air inlet duct door 10 Recirculated air inlet 11 19805 Blower motor 19 Floor/defrost door (full vacuum position) (part of 18471) 20 Defrost airflow Vacuum Connector End View 12 18476 Heater core 13 Vacuum from the engine Hose intake manifold (gas engine) Port Color Function or vacuum pump (diesel 1 White Recirculation air duct door engine) 2 Red Floor/defrost door 14 19A563 A/C vacuum check valve 3 Yellow Floor/defrost door 15 19A566 A/C vacuum reservoir tank and bracket 4 Blue Floor/panel door 16 19B888 Function selector switch 5 Black Vacuum source 17 Floor air flow 6 t used 18 18A318 Vacuum control motor floor/defrost door Vacuum Application Chart Switch Port Color Function Function Selector Switch Position MAX NORM A/C A/C VENT OFF FLOOR MIX DEF 1 White Recirc/ fresh V NV NV V NV NV NV 2 Red Floor/ defrost V V V V V NV NV 3 Yellow Floor/ defrost V V V V V V NV 4 Blue Floor/ panel V V V NV NV NV NV 5 Black Vacuum source V V V V V V V V = Vacuum 2. Inspect to determine if one of the following NV = Vacuum mechanical or electrical concerns apply: Inspection and Verification 1. Verify the customer s concern by operating the climate control system to duplicate the condition.

412-00-4 Climate Control System - General Information 412-00-4 DIAGNOSIS AND TESTING Visual Inspection Chart check the ignition switch position. Mechanical Electrical 6. If the scan tool still does not allow with the Loose, missing, or Open fuses. vehicle selection to be entered, refer to the scan damaged A/C Blower motor tool manual. compressor drive belt. inoperative. Loose or disconnected A/C compressor 7. Carry out the DATA LINK DIAGNOSTIC A/C clutch. inoperative. TEST using the scan tool. If the scan tool Loose, misrouted or Circuitry open/shorted. responds with: damaged vacuum lines a Disconnected electrical SCP+, SCP-, or UBP CIRCUITS FAULT =. connectors. Broken or leaking ALL ECUS NO RESP/NOT EQUIP, refer vacuum control motor a. to Section 418-00 to diagnose the network Broken or leaking concern. refrigerant lines. If the powertrain control module (PCM) a A leak in the vacuum control circuit may occur (12A650) is not listed for a communication during acceleration (slow leak), may exist at all concern, turn the A/C controls to OFF and times (large leak), and may exist only when specific carry out the self-test diagnostics for the functions are selected (indicating a leak in that PCM. portion of the circuit). The vacuum hoses used in the passenger compartment control circuit are 8. If any PCM diagnostic trouble codes (DTCs) constructed from PVC plastic material. The vacuum are retrieved and related to the concern, go to hoses used in the engine compartment are the Diagnostic Trouble Code (DTC) Index to constructed of Hytrel. Because of the materials used, never pinch the vacuum hoses off during continue diagnostics. diagnosis to locate a leak. A wood golf tee can be 9. If no DTCs related to the concern are retrieved, used as a plug when it is necessary to plug one end of the vacuum hose for leak test purposes. GO to Symptom Chart to continue diagnostics. Diagnostic Trouble Code (DTC) Index 3. As pinpoint tests and measurements are being DTC Description Action carried out, be sure to inspect for any disconnected, loose fitting, or incorrectly P1460 Wide open throttle REFER to the A/C primary circuit Powertrain installed component, module and in-line malfunction Control/Emissions electrical connectors and pins. Diagnosis (PC/ED) 4. If an obvious cause for an observed or reported manual. concern is found, correct the cause (if possible) P1464 A/C demand out of REFER to the before proceeding to the next step. self-test range Powertrain 5. Control/Emissions If the cause is not visually evident, connect a Diagnosis (PC/ED) scan tool to the data link connector and select manual. the vehicle to be tested from the scan tool P1469 Low A/C cycling REFER to the menu. If the scan tool does not communicate period Powertrain with the vehicle: Control/Emissions Diagnosis (PC/ED) check that the program card is correctly manual. installed. check the connections to the vehicle.

412-00-5 Climate Control System - General Information 412-00-5 DIAGNOSIS AND TESTING Symptom Chart Symptom Chart Condition Possible Sources Action Incorrect/erratic direction of Function selector switch. GO to Pinpoint Test A. airflow from outlets Vacuum hose/harness. Vacuum control motor. A/C vacuum check valve. Vacuum reservoir tank. Air distribution door/linkage. Insufficient, erratic, or no Low engine coolant level. GO to Pinpoint Test B. heat Engine overheating. Plugged or partially plugged heater core. Temperature blend door binding/stuck. Temperature blend door actuator. The air conditioning (A/C) is Fuse(s). GO to Pinpoint Test C. inoperative/does not operate Circuitry open/short. correctly gasoline engines A/C cycling switch. Low refrigerant system charge. Function selector switch. Pressure cutoff switch. A/C compressor clutch air gap. A/C compressor clutch field coil. The air conditioning (A/C) is Fuse(s). GO to Pinpoint Test D. inoperative/does not operate Circuitry open/short. correctly diesel engine A/C cycling switch. Low refrigerant system charge. Function selector switch. Pressure cutoff switch. A/C control relay. Powertrain control module (PCM). A/C compressor clutch air gap. A/C compressor clutch field coil. The air conditioning (A/C) is Circuitry short. GO to Pinpoint Test E. always on gasoline Function selector switch. engines A/C compressor clutch air gap. The air conditioning (A/C) is Circuitry short. GO to Pinpoint Test F. always on diesel engine Function selector switch. A/C control relay. PCM. A/C compressor clutch air gap. Insufficient air conditioning Low refrigerant level. CARRY OUT the refrigerant (A/C) cooling Temperature blend door system tests. REFER to actuator. Refrigerant System Tests in this section. If OK, GO to Pinpoint Test H.

412-00-6 Climate Control System - General Information 412-00-6 DIAGNOSIS AND TESTING Symptom Chart Condition Possible Sources Action Insufficient air conditioning Thermostatic expansion valve. GO to Pinpoint Test G. (A/C) cooling auxiliary Leaking or restricted vacuum system hose. Vacuum control motor. Sticking mode door. Temperature control is Circuitry open/short. GO to Pinpoint Test H. inoperative/does not operate Temperature blend door correctly actuator. Temperature control switch. The blower motor is Fuse(s). GO to Pinpoint Test I. inoperative Circuitry open/short. Blower motor relay. Function selector switch. Blower motor. The blower motor does not Blower motor switch. GO to Pinpoint Test J. operate correctly Blower motor resistor. Circuitry open/short. The auxiliary blower motor is Fuse(s). GO to Pinpoint Test K. inoperative Circuitry open/short. Auxiliary blower motor relay. Auxiliary blower motor switch. Auxiliary high speed blower motor relay. Auxiliary blower motor. The auxiliary blower motor Auxiliary blower motor GO to Pinpoint Test L. does not operate correctly switch. Auxiliary blower motor resistor. Circuitry open/short. The auxiliary Auxiliary temperature If both temperature and mode temperature/mode is actuator. are affected, REPAIR the inoperative/does not operate Auxiliary mode actuator. vacuum source line for an correctly Auxiliary vacuum source line. obstruction or leak. TEST the system for normal operation. If the temperature or mode alone are affected, inspect the temperature or mode door for a binding or broken condition. If no condition is found, INSTALL a new actuator. TEST the system for normal operation. Pinpoint Tests A1 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE SYSTEM AIRFLOW Key in ON position. With the engine running, set the blower motor switch to HI.

412-00-7 Climate Control System - General Information 412-00-7 DIAGNOSIS AND TESTING A1 A2 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE SYSTEM AIRFLOW Check the system airflow in each function selector switch position to determine which position(s) have incorrect airflow. Refer to the vacuum schematic in this section. GO to A2. Is the airflow coming from the defroster nozzles in all of the positions? GO to A14. CHECK THE VACUUM SUPPLY HOSE Check the vacuum supply hose to be sure that it is connected. A3 RECONNECT the vacuum supply hose. GO to A13. Is the vacuum supply hose disconnected? GO to A3. LEAK CHECK THE VACUUM TANK AND HOSES NOTE: The in-line vacuum harness connector is located in the vehicle, below the instrument panel, on the passenger side. Disconnect: Intake Manifold Vacuum Hose. Disconnect: In-Line Vacuum Harness. Plug the vacuum supply hose at the intake manifold.

412-00-8 Climate Control System - General Information 412-00-8 DIAGNOSIS AND TESTING A3 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS LEAK CHECK THE VACUUM TANK AND HOSES Carry out a vacuum leak test on the vacuum tank, check valve and hoses. Connect the vacuum pump to the plenum vacuum harness connector. Apply a vacuum. Check for a vacuum leak. A4 GO to A4. Is there leakage? GO to A9. LEAK CHECK THE VACUUM SUPPLY HOSE Remove the evaporator core housing. Refer to Section 412-02. Disconnect: Vacuum Supply Hose. Carry out a vacuum leak test on the vacuum supply hose. Plug one end of the hose. Connect the vacuum pump to the other end. Apply a vacuum. Check for a vacuum leak. A5 REPAIR or INSTALL a new vacuum supply hose. TEST the system for normal operation. Does the hose leak? GO to A5. INSPECT THE A/C VACUUM CHECK VALVE Disconnect: A/C Vacuum Check Valve.

412-00-9 Climate Control System - General Information 412-00-9 DIAGNOSIS AND TESTING A5 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS INSPECT THE A/C VACUUM CHECK VALVE Inspect the A/C vacuum check valve for any obstructions and correct operation. Airflow through the A/C vacuum check valve must be directed toward the engine. A6 INSTALL a new A/C vacuum check valve (19A563). TEST the system for normal operation. Is the A/C vacuum check valve plugged or obstructed? GO to A6. LEAK TEST THE A/C VACUUM CHECK VALVE Carry out a vacuum leak test on the A/C vacuum check valve. Connect two hoses and a tee fitting to the outlet ports of the A/C vacuum check valve. Connect the tee fitting to the vacuum pump. Apply 51 kpa (15 in-hg) of vacuum.

412-00-10 Climate Control System - General Information 412-00-10 DIAGNOSIS AND TESTING A6 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS LEAK TEST THE A/C VACUUM CHECK VALVE If the vacuum loss exceeds 3.37 kpa (1 in-hg) per minute, then remove the A/C vacuum check valve and carry out a vacuum leak test on the vacuum pump. Plug both of the hoses. Apply a vacuum. A7 INSTALL a new A/C vacuum check valve (19A563). TEST the system for normal If the vacuum pump loses vacuum, then correct the problem and operation. repeat this procedure. Does the A/C vacuum check valve leak? GO to A7. CHECK THE VACUUM RESERVOIR Disconnect: Vacuum Reservoir. Carry out a vacuum leak test on the vacuum reservoir tank. Connect the vacuum pump to the vacuum reservoir tank. Apply a vacuum. Check for a vacuum leak. INSTALL a new vacuum reservoir tank (19A566). TEST the system for normal operation. Does the vacuum reservoir tank leak? GO to A8.

412-00-11 Climate Control System - General Information 412-00-11 DIAGNOSIS AND TESTING A8 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE SUPPLY HOSE Check the supply hose for a vacuum leak. Connect the vacuum pump to the supply hose of the plenum vacuum harness. Install a plug in the other end of the hose. Apply a vacuum. Check for a vacuum leak. Check the supply hose for a restriction or blockage. Remove the plug. Apply a vacuum. Check for a restriction or blockage. A9 REPAIR or INSTALL a new supply hose. TEST the system for normal operation. Does the supply hose have a leak, restriction, or blockage? GO to A9. CHECK THE JUMPER VACUUM HARNESS SUPPLY HOSE Disconnect the jumper vacuum harness from the function selector switch.

412-00-12 Climate Control System - General Information 412-00-12 DIAGNOSIS AND TESTING A9 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE JUMPER VACUUM HARNESS SUPPLY HOSE Check the jumper vacuum harness supply hose for a vacuum leak. Connect the vacuum pump to one end of the jumper vacuum harness supply hose. Install a plug in the other end of the hose. Apply a vacuum. Check for a vacuum leak. Check the jumper vacuum harness supply hose for a restriction or blockage. Remove the plug. Apply a vacuum. Check for a restriction or blockage. A10 REPAIR or INSTALL a new jumper vacuum harness. TEST the system for normal operation. Does the jumper vacuum harness supply hose have a leak, restriction, or blockage? GO to A10. CHECK THE FUNCTION SELECTOR SWITCH Connect the jumper vacuum harness to the function selector switch.

412-00-13 Climate Control System - General Information 412-00-13 DIAGNOSIS AND TESTING A10 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE FUNCTION SELECTOR SWITCH Carry out a vacuum leak test on each function selector switch position. Plug all of the vacuum hoses except for the function selector switch supply hose. Connect the vacuum pump to the function selector switch supply hose. Apply 51 kpa (15 in-hg) of vacuum at each function selector switch position. Check for a vacuum drop exceeding 3.37 kpa (1 in-hg) per minute. A11 NOTE which function selector switch position(s) leak. GO to A11. Does the vacuum drop more than 3.37 kpa (1 in-hg) per minute? GO to A15. LEAK TEST THE CONTROL ASSEMBLY Disconnect the jumper vacuum harness from the function selector switch.

412-00-14 Climate Control System - General Information 412-00-14 DIAGNOSIS AND TESTING A11 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS LEAK TEST THE CONTROL ASSEMBLY Carry out a vacuum leak test on the function selector switch for the positions that were noted in Step A10. Plug the leaking control port(s), as noted in Step A10. Connect the vacuum pump to the function selector switch supply port. Select the corresponding function selector switch position. Apply 51 kpa (15 in-hg) of vacuum. Check for a vacuum drop exceeding 1.68 kpa (1/2 in-hg) per minute. A12 INSTALL a new function selector switch (19B888). TEST the system for normal operation. Does the vacuum drop more than 1.68 kpa (1/2 in-hg) per minute? GO to A12. LEAK TEST THE PLENUM VACUUM HARNESS Disconnect the vacuum hose(s) that indicated a leak in Step A10 from the corresponding vacuum control motor.

412-00-15 Climate Control System - General Information 412-00-15 DIAGNOSIS AND TESTING A12 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS LEAK TEST THE PLENUM VACUUM HARNESS Carry out a vacuum leak test on each of the hose(s). Connect the vacuum pump to one end of the vacuum hose. Install a plug in the other end of the hose. Apply 51 kpa (15 in-hg) of vacuum. Check for a vacuum leak. A13 A14 REPAIR or INSTALL a new plenum vacuum harness. TEST the system for normal operation. CHECK the plenum vacuum harness connection. REPAIR or INSTALL a new plenum vacuum harness as necessary. Do the vacuum hose(s) leak? TEST the system for normal operation. EVALUATE THE SYSTEM AIRFLOW Check the airflow that was noted in Step A1 for each function selector switch position. GO to A14. Is the airflow in Step A1 correct for each function selector switch position? GO to A15. ISOLATE THE LEAKING VACUUM CIRCUIT Key in ON position. With the engine running, set the blower motor switch to HI. Cycle the function selector switch to each function selector switch position during acceleration. A15 Check for a variation in the system airflow for each function GO to A19. selector switch position during acceleration. Does the airflow go to defrost during engine acceleration? GO to A15. REVIEW THE VEHICLE HISTORY Review the vehicle history to determine if the system operated GO to A18. correctly prior to the complaint. Did the system operate correctly prior to this complaint? GO to A16.

412-00-16 Climate Control System - General Information 412-00-16 DIAGNOSIS AND TESTING A16 A17 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE VACUUM HARNESSES Compare the colors on each vacuum hose to those shown on the vacuum schematic. Refer to the vacuum schematic in the GO to A17. Diagnosis and Testing portion of this section. Do the vacuum hoses agree with what is shown on the CORRECT or INSTALL a new plenum vacuum schematic? vacuum harness or jumper vacuum harness. TEST the system for normal operation. CHECK THE VACUUM CIRCUIT Inspect each vacuum hose to determine if it is pinched or kinked. A18 REPAIR the damaged vacuum hose(s) or INSTALL a new plenum vacuum harness. TEST the system for normal operation. Are any of the vacuum hoses pinched or kinked? GO to A18. CHECK THE VACUUM CIRCUIT CONNECTIONS Check vacuum hose connections to determine if any are disconnected or partially connected. A19 RECONNECT the vacuum hose(s). TEST the system for normal operation. Are any of the vacuum hoses disconnected or partially connected? GO to A19. CHECK THE VACUUM HOSES Disconnect each suspected vacuum hose from the system.

412-00-17 Climate Control System - General Information 412-00-17 DIAGNOSIS AND TESTING A19 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE VACUUM HOSES Carry out a vacuum leak test on each suspected hose. Connect the vacuum pump to one end of the vacuum hose. Install a plug in the other end of the hose. Apply a vacuum. Check for a vacuum leak. Check each suspected hose for a restriction or blockage. Remove the plug. Apply a vacuum. Check for a restriction or blockage. A20 REPAIR the vacuum hose(s) or INSTALL a new plenum vacuum harness or jumper vacuum harness. TEST the system for normal operation. Do any of the vacuum hose(s) have a leak, restriction, or blockage? GO to A20. CHECK THE VACUUM CONTROL MOTOR Disconnect the suspected vacuum control motor.

412-00-18 Climate Control System - General Information 412-00-18 DIAGNOSIS AND TESTING A20 PINPOINT TEST A: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS CHECK THE VACUUM CONTROL MOTOR Carry out a vacuum leak test on each of the suspected vacuum control motor(s). Connect the vacuum pump to the vacuum control motor(s). Apply a vacuum. A21 INSTALL a new vacuum control motor(s) (18A318). TEST the system for normal operation. Do any of the suspected vacuum control motor(s) leak? GO to A21. CHECK THE VACUUM MOTOR INSTALLATION Check for correct attachment of the vacuum control motor arm to the air distribution door or air distribution door crank arm. INSPECT for a binding or damaged air distribution door. REPAIR or INSTALL a new air distribution door as necessary. TEST the system for normal operation. CONNECT the vacuum motor arm to the air distribution door or air distribution door Is the vacuum motor arm correctly attached to the air crank arm. TEST the system for normal distribution door or air distribution door crank arm? operation. B1 PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT CHECK FOR CORRECT ENGINE COOLANT LEVEL WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, (still with a cloth) turn and remove the pressure relief cap. GO to B3. Check the engine coolant level. Is the engine coolant at the correct level? GO to B2.

412-00-19 Climate Control System - General Information 412-00-19 DIAGNOSIS AND TESTING B2 B3 PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT CHECK THE ENGINE COOLING SYSTEM FOR LEAKS Pressure test the cooling system for leaks. Refer to Section 303-03. REPAIR the engine coolant leak. TEST Does the engine cooling system leak? the system for normal operation. GO to B3. CHECK FOR HOT COOLANT TO THE HEATER CORE INLET HOSE Allow the engine to reach normal operating temperature. WARNING: Do not stand in line with or near the fan blade when the engine is running. WARNING: The heater core inlet hose will become too hot to handle and can cause serious burns if the system is working correctly. Lightly touch the heater core inlet hose. B4 GO to B4. Is the heater core inlet hose hot? GO to Section 303-03. CHECK THE HEATER CORE OUTLET HOSE FOR HOT COOLANT Allow the engine to reach normal operating temperature.

412-00-20 Climate Control System - General Information 412-00-20 DIAGNOSIS AND TESTING B4 PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT CHECK THE HEATER CORE OUTLET HOSE FOR HOT COOLANT WARNING: Do not stand in line with or near the fan blade when the engine is running. WARNING: The heater core outlet hose will become too hot to handle and can cause serious burns if the system is working correctly. Lightly touch the heater core outlet hose. TEST the heater core (18476) for a plugged or partial plugged condition. Is the heater core outlet hose cool or cold? GO to Pinpoint Test H. PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C1 NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kpa (42 psi). If the pressure is below 290 kpa (42 psi), refer to Fluorescent Dye Leak Detection. CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL Disconnect: A/C Compressor Clutch Field Coil C100. Key in ON position. With the engine running, place the function selector switch in MAX A/C.

412-00-21 Climate Control System - General Information 412-00-21 DIAGNOSIS AND TESTING PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C1 CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL Measure the voltage between A/C compressor clutch field coil C100, circuit 347 (BK/YE) and ground. C2 GO to C2. Is the voltage greater than 10 volts? GO to C4. CHECK CIRCUIT 57 (BK) Measure the resistance between A/C compressor clutch field coil C100, circuit 57 (BK) and ground. C3 GO to C3. REPAIR circuit 57 (BK) for an open. TEST Is the resistance less than 5 ohms? the system for normal operation. CHECK THE A/C COMPRESSOR CLUTCH AIR GAP Measure the A/C compressor clutch air gap at three equally spaced locations between the clutch disc and hub assembly and the A/C compressor clutch pulley. ADJUST the A/C compressor clutch air gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment in this section. TEST the system for normal operation. INSTALL a new A/C compressor clutch Is the A/C compressor clutch air gap greater than 0.75 mm field coil. REFER to Section 412-03A. (0.030 in)? TEST the system for normal operation.

412-00-22 Climate Control System - General Information 412-00-22 DIAGNOSIS AND TESTING PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C4 CHECK THE VOLTAGE TO THE PRESSURE CUTOFF SWITCH Disconnect: Pressure Cutoff Switch C1078. Key in ON position. Measure the voltage between pressure cutoff switch C1078 pin 3, circuit 441 (RD/YE) and ground. C5 GO to C8. Is the voltage greater than 10 volts? GO to C5. CHECK THE VOLTAGE TO THE A/C CYCLING SWITCH Disconnect: A/C Cycling Switch C130. Key in ON position. Measure the voltage between A/C cycling switch C130 pin 1, circuit 348 (VT) and ground. C6 GO to C6. Is the voltage greater than 10 volts? GO to C9. CHECK THE A/C CYCLING SWITCH

412-00-23 Climate Control System - General Information 412-00-23 DIAGNOSIS AND TESTING PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C6 CHECK THE A/C CYCLING SWITCH Connect a fused jumper wire between A/C cycling switch C130 pin 1, circuit 348 (VT) and pin 4, circuit 441 (RD/YE). Key in ON position. Measure the voltage between pressure cutoff switch C1078 pin 3, circuit 441 (RD/YE) and ground. C7 C8 GO to C7. REPAIR circuit 441 (RD/YE) for an open. Is the voltage greater than 10 volts? TEST the system for normal operation. CHECK THE REFRIGERANT SYSTEM PRESSURE Connect the manifold gauge set. INSTALL a new A/C cycling switch. TEST Is the A/C system pressure between 345 kpa (50 psi) and the system for normal operation. 1724 kpa (250 psi)? TEST/REPAIR the refrigerant system for leaks. TEST the system for normal operation. CHECK CIRCUIT 347 (BK/YE)

412-00-24 Climate Control System - General Information 412-00-24 DIAGNOSIS AND TESTING PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C8 CHECK CIRCUIT 347 (BK/YE) Measure the resistance between pressure cutoff switch C1078 pin 1, circuit 347 (BK/YE) and A/C compressor clutch field coil C100, circuit 347 (BK/YE). C9 INSTALL a new pressure cutoff switch (19D594). TEST the system for normal operation. REPAIR circuit 347 (BK/YE) for an open. Is the resistance less than 5 ohms? TEST the system for normal operation. CHECK THE VOLTAGE AT THE FUNCTION SELECTOR SWITCH Disconnect: Function Selector Switch C294a. Key in ON position. Measure the voltage between function selector switch C294a pin 4, circuit 489 (PK/BK) and ground. C10 GO to C10. REPAIR circuit 489 (PK/BK) for an open. Is the voltage greater than 10 volts? TEST the system for normal operation. CHECK CIRCUIT 348 (VT)

412-00-25 Climate Control System - General Information 412-00-25 DIAGNOSIS AND TESTING PINPOINT TEST C: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY GASOLINE ENGINES C10 CHECK CIRCUIT 348 (VT) Measure the resistance between function selector switch C294a pin 2, circuit 348 (VT) and A/C cycling switch C130 pin 1, circuit 348 (VT). INSTALL a new function selector switch (19B888). TEST the system for normal operation. REPAIR circuit 348 (VT) for an open. Is the resistance less than 5 ohms? TEST the system for normal operation. PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D1 D2 D3 D4 NOTE: Before carrying out the following test, diagnose any PCM DTCs. NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kpa (42 psi). If the pressure is below 290 kpa (42 psi), refer to Fluorescent Dye Leak Detection. CHECK DAYTIME RUNNING LAMP OPERATION Key in ON position. Observe the daytime running lamps. GO to D2. Do the daytime running lamps operate? VERIFY the battery junction box (BJB) fuse 3 (10A) or 3 (15A) is OK. If the fuse is OK, GO to D2. If the fuse is open, INSTALL a new 15A fuse and TEST the system for normal operation. If fuse opens again, REPAIR the circuit for a short. CHECK PID ACCS WITH THE A/C OFF Key in ON position. With the engine running, place the function selector switch to the OFF position. Enter the following diagnostic mode on the scan tool: PCM PID GO to Pinpoint Test F. ACCS. Does the PCM PID ACCS read ON? GO to D3. CHECK PID WAC WITH THE A/C OFF Enter the following diagnostic mode on the scan tool: PCM PID WAC. REFER to Powertrain Control/Emissions Does the PCM PID WAC read ON? Diagnosis (PC/ED) manual. GO to D4. CHECK THE PID ACCS WITH THE A/C ON Enter the following diagnostic mode on the scan tool: PCM PID ACCS. GO to D5. Place the function selector switch in the MAX A/C position. Does the PCM PID ACCS read ON? GO to D6.

412-00-26 Climate Control System - General Information 412-00-26 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D5 D6 CHECK THE PID WAC WITH THE A/C ON Enter the following diagnostic mode on the scan tool: PCM PID WAC. GO to D14. Does the PCM PID WAC read ON? REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual. CHECK THE A/C PRESSURE CUTOFF SWITCH VOLTAGE Disconnect: A/C Pressure Cutoff Switch C1078. Key in ON position. Measure the voltage between A/C pressure cutoff switch C1078, circuit 441 (RD/YE) and ground. D7 GO to D12. Is the voltage greater than 10 volts? GO to D7. CHECK THE A/C CYCLING SWITCH VOLTAGE Disconnect: A/C Cycling Switch C130. Key in ON position. Measure the voltage between A/C cycling switch C130, circuit 348 (VT) and ground. D8 GO to D8. Is the voltage greater than 10 volts? GO to D9. CHECK THE A/C CYCLING SWITCH

412-00-27 Climate Control System - General Information 412-00-27 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D8 CHECK THE A/C CYCLING SWITCH Measure the resistance between the A/C cycling switch terminals. D9 REPAIR circuit 441 (RD/YE). TEST the system for normal operation. Is the resistance less than 21 ohms? GO to D11. CHECK THE VOLTAGE AT THE FUNCTION SELECTOR SWITCH Disconnect: Function Selector Switch C294a. Key in ON position. Measure the voltage between function selector switch C294a pin 1, circuit 296 (WH/VT) and ground. D10 GO to D10. REPAIR circuit 296 (WH/VT). TEST the Is the voltage greater than 10 volts? system for normal operation. CHECK CIRCUIT 348 (VT) FOR AN OPEN Measure the resistance between function selector switch C294a, circuit 348 (VT) and A/C cycling switch C130, circuit 348 (VT). INSTALL a new function selector switch. REFER to Section 412-04. TEST the system for normal operation. REPAIR circuit 348 (VT). TEST the Is the resistance less than 5 ohms? system for normal operation.

412-00-28 Climate Control System - General Information 412-00-28 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D11 D12 CHECK THE A/C SYSTEM PRESSURE Connect the manifold gauge set. INSTALL a new A/C cycling switch. TEST Is the pressure reading between 345 kpa (50 psi) and 1724 the system for normal operation. kpa (250 psi)? CHECK the system for refrigerant leaks. REFER to Electronic Leak Detection and Fluorescent Dye Leak Detection in this section. CHECK THE A/C PRESSURE CUTOFF SWITCH Connect a fused jumper lead between A/C pressure cutoff switch C1078, circuit 441 (RD/YE) and circuit 347 (BK/YE). D13 INSTALL a new A/C pressure cutoff switch (19D594). TEST the system for normal operation. Key in START position. Does the A/C compressor operate? GO to D13. CHECK CIRCUIT 347 (BK/YE) Remove the fused jumper lead from A/C pressure cutoff switch C1078. Disconnect: PCM C176a. Measure the resistance between A/C pressure cutoff switch C1078, circuit 347 (BK/YE) and PCM C176a pin 8, circuit 347 (BK/YE). D14 INSTALL a new PCM. REFER to Section 303-14A. REPAIR circuit 347 (BK/YE). TEST the Is the resistance less than 5 ohms? system for normal operation. CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL Disconnect: A/C Compressor Clutch Field Coil C100. Key in ON position.

412-00-29 Climate Control System - General Information 412-00-29 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D14 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL Measure the voltage between A/C compressor clutch field coil C100, circuit 321 (GY/WH) and ground. D15 GO to D15. Is the voltage greater than 10 volts? GO to D16. CHECK THE GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL Measure the resistance between A/C compressor clutch field coil C100, circuit 57 (BK) and ground. D16 GO to D18. REPAIR circuit 57 (BK). TEST the system Is the resistance less than 5 ohms? for normal operation. CHECK CIRCUIT 932 (GY/WH) Disconnect: A/C Control Relay.

412-00-30 Climate Control System - General Information 412-00-30 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D16 CHECK CIRCUIT 932 (GY/WH) Measure the voltage between A/C control relay socket pin 3, circuit 932 (GY/WH) and ground. D17 GO to D17. VERIFY the battery junction box (BJB) fuse 3 (10A) or 3 (15A) is OK. If OK, REPAIR circuit 932 (GY/WH) for an open. TEST the system for normal operation. If the fuse is open, INSTALL a new 15A fuse. If the fuse opens again, REPAIR the Is the voltage greater than 10 volts? circuit for a short. CHECK CIRCUIT 321 (GY/WH) Measure the resistance between A/C control relay socket pin 5, circuit 321 (GY/WH) and A/C compressor clutch field coil C100, circuit 321 (GY/WH). D18 GO to D19. REPAIR circuit 321 (BY/WH). TEST the Is the resistance less than 5 ohms? system for normal operation. CHECK THE A/C COMPRESSOR CLUTCH AIR GAP Measure the A/C compressor clutch air gap at three equally spaced locations between the clutch disc and hub assembly and the A/C compressor clutch pulley. ADJUST the A/C compressor clutch air gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment in this section. TEST the system for normal operation. INSTALL a new A/C compressor clutch Is the A/C compressor clutch air gap greater than 0.75 mm field coil. REFER to Section 412-03A. (0.030 in)? TEST the system for normal operation.

412-00-31 Climate Control System - General Information 412-00-31 DIAGNOSIS AND TESTING PINPOINT TEST D: THE AIR CONDITIONING (A/C) IS INOPERATIVE/DOES NOT OPERATE CORRECTLY DIESEL ENGINE D19 CHECK THE WAC OUTPUT FROM THE PCM Key in ON position. With the engine running, measure the voltage between A/C control relay socket pin 1, circuit 331 (PK/YE) and pin 2, circuit 361 (RD). D20 INSTALL a new A/C control relay. CLEAR the DTCs. TEST the system for normal operation. Is the voltage greater than 10 volts? GO to D20. CHECK VOLTAGE TO A/C CLUTCH RELAY COIL Measure the voltage between A/C control relay socket pin 2, circuit 361 (RD) and ground. D21 GO to D21. REPAIR circuit 361 (RD) for an open. Is the voltage greater than 10 volts? TEST the system for normal operation. CHECK CIRCUIT 331 (PK/YE) Disconnect: PCM C176a. Measure the resistance between A/C control relay socket pin 1, circuit 331 (PK/YE) and PCM C176a pin 2, circuit 331 (PK/YE). INSTALL a new PCM. REFER to Section 303-14A. TEST the system for normal operation. REPAIR circuit 331 (PK/YE). CLEAR the DTCs. TEST the system for normal Is the resistance less than 5 ohms? operation.

412-00-32 Climate Control System - General Information 412-00-32 DIAGNOSIS AND TESTING E1 PINPOINT TEST E: THE AIR CONDITIONING (A/C) IS ALWAYS ON GASOLINE ENGINES CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL Disconnect: A/C Compressor Clutch Field Coil C100. Key in ON position. Place the function selector switch in the OFF position. Measure the voltage between A/C compressor clutch field coil C100, circuit 347 (BK/YE) and ground. E2 GO to E2. ADJUST the A/C compressor clutch air gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment in this section. Is voltage present? TEST the system for normal operation. CHECK FOR VOLTAGE TO THE A/C CYCLING SWITCH Disconnect: A/C Cycling Switch C130. Key in ON position. Measure the voltage between A/C cycling switch C130 pin 1, circuit 348 (VT) and ground. E3 GO to E3. Is voltage present? GO to E4. CHECK CIRCUIT 348 (VT) FOR A SHORT TO VOLTAGE Disconnect: Function Selector Switch C294a. Key in ON position.

412-00-33 Climate Control System - General Information 412-00-33 DIAGNOSIS AND TESTING PINPOINT TEST E: THE AIR CONDITIONING (A/C) IS ALWAYS ON GASOLINE ENGINES E3 CHECK CIRCUIT 348 (VT) FOR A SHORT TO VOLTAGE Measure the voltage between A/C cycling switch C130 pin 1, circuit 348 (VT) and ground. E4 REPAIR circuit 348 (VT) for a short to voltage. TEST the system for normal operation. INSTALL a new function selector switch (19B888). TEST the system for normal Is voltage present? operation. CHECK CIRCUIT 441 (RD/YE) FOR A SHORT TO VOLTAGE Disconnect: Pressure Cutoff Switch C1078. Key in ON position. Measure the voltage between pressure cutoff switch C1078 pin 3, circuit 441 (RD/YE) and ground. REPAIR circuit 347 (BK/YE) for a short to voltage. TEST the system for normal operation. REPAIR circuit 441 (RD/YE) for a short to voltage. TEST the system for normal Is voltage present? operation. F1 F2 F3 PINPOINT TEST F: THE AIR CONDITIONING (A/C) IS ALWAYS ON DIESEL ENGINE NOTE: Before carrying out the following test, diagnose any PCM DTCs. CHECK PID WACF WITH THE A/C OFF Key in ON position. Place the function selector switch to the OFF position. REPAIR circuit 331 (PK/YE). TEST the Enter the following diagnostic mode on the scan tool: PCM PID system for normal operation. WACF. Does the PCM PID WACF read YES? GO to F2. CHECK PID ACCS WITH THE A/C OFF Enter the following diagnostic mode on the scan tool: PCM PID ACCS. GO to F3. Does the PCM PID ACCS read ON? GO to F7. CHECK FOR VOLTAGE AT THE A/C CYCLING SWITCH

412-00-34 Climate Control System - General Information 412-00-34 DIAGNOSIS AND TESTING F3 PINPOINT TEST F: THE AIR CONDITIONING (A/C) IS ALWAYS ON DIESEL ENGINE CHECK FOR VOLTAGE AT THE A/C CYCLING SWITCH Disconnect: A/C Cycling Switch C1081. Key in ON position. Measure the voltage between A/C cycling switch C1081, circuit 348 (VT) and ground. F4 GO to F4. Is voltage present? GO to F5. CHECK CIRCUIT 348 (VT) FOR A SHORT TO VOLTAGE Disconnect: Function Selector Switch C294a. Key in ON position. Measure the voltage between A/C cycling switch C1081, circuit 348 (VT) and ground. F5 REPAIR circuit 348 (VT) for a short to voltage. TEST the system for normal operation. INSTALL a new function selector switch. REFER to Section 412-04. TEST the Is voltage present? system for normal operation. CHECK CIRCUIT 441 (RD/YE) FOR A SHORT TO VOLTAGE Disconnect: A/C Pressure Cutoff Switch C1078. Key in ON position.

412-00-35 Climate Control System - General Information 412-00-35 DIAGNOSIS AND TESTING F5 PINPOINT TEST F: THE AIR CONDITIONING (A/C) IS ALWAYS ON DIESEL ENGINE CHECK CIRCUIT 441 (RD/YE) FOR A SHORT TO VOLTAGE Measure the voltage between A/C pressure cutoff switch C1078, circuit 441 (RD/YE) and ground. F6 REPAIR circuit 441 (RD/YE) for a short to voltage. TEST the system for normal operation. Is voltage present? GO to F6. CHECK CIRCUIT 347 (BK/YE) FOR A SHORT TO VOLTAGE Measure the voltage between A/C pressure cutoff switch C1078, circuit 347 (BK/YE) and ground. F7 REPAIR circuit 347 (BK/YE) for a short to voltage. TEST the system for normal operation. INSTALL a new PCM. REFER to Section 303-14A. TEST the system for normal Is voltage present? operation. CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL Disconnect: A/C Compressor Clutch Field Coil C100. Key in ON position. Measure the voltage between A/C compressor clutch field coil C100, circuit 321 (GY/WH) and ground. GO to F8. ADJUST the A/C compressor clutch air gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment in this section. Is voltage present? TEST the system for normal operation.

412-00-36 Climate Control System - General Information 412-00-36 DIAGNOSIS AND TESTING F8 PINPOINT TEST F: THE AIR CONDITIONING (A/C) IS ALWAYS ON DIESEL ENGINE CHECK CIRCUIT 321 (GY/WH) FOR A SHORT TO VOLTAGE Disconnect: A/C Control Relay. Key in ON position. Measure the voltage between A/C compressor clutch field coil C100, circuit 321 (GY/WH) and ground. G1 G2 REPAIR circuit 321 (GY/WH) for a short to voltage. TEST the system for normal operation. INSTALL a new A/C control relay. TEST Is voltage present? the system for normal operation. PINPOINT TEST G: INSUFFICIENT AIR CONDITIONING (A/C) COOLING AUXILIARY SYSTEM CHECK THE MODE DOOR OPERATION Remove the rear lower body side trim panel. Refer to Section 501-05. Key in ON position. CHECK the thermostatic expansion valve With the engine running, cycle the function selector switch (19849) for correct operation. INSTALL a between FLR and NORM A/C or MAX A/C. new valve if necessary. TEST the system Check the mode door for operation between the heater core and for normal operation. evaporator core positions. Does the mode door operate correctly? GO to G2. CHECK FOR SOURCE VACUUM Disconnect: Auxiliary Vacuum Control Motor. Connect the vacuum pump to the vacuum supply hose. Key in ON position. With the engine running, cycle the function selector switch from FLR to NORM A/C or MAX A/C. Measure the supply hose vacuum. G3 GO to G3. LOCATE the vacuum hose restriction or leak. REPAIR the vacuum hose as necessary. TEST the system for normal Is the vacuum between 61-71 kpa (18-21 in-hg)? operation. CHECK THE VACUUM CONTROL MOTOR

412-00-37 Climate Control System - General Information 412-00-37 DIAGNOSIS AND TESTING G3 PINPOINT TEST G: INSUFFICIENT AIR CONDITIONING (A/C) COOLING AUXILIARY SYSTEM CHECK THE VACUUM CONTROL MOTOR Carry out a vacuum leak test on the auxiliary vacuum control motor. Connect the vacuum pump to the auxiliary vacuum control motor. Apply 61-71 kpa (18-21 in-hg) of vacuum to the auxiliary vacuum control motor. Check for a vacuum drop. INSTALL a new vacuum control motor (18A318). TEST the system for normal operation. CHECK for a sticking mode door and REPAIR as necessary. TEST the system Does the vacuum drop? for normal operation. PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H1 CHECK THE VOLTAGE TO THE BLEND DOOR ACTUATOR Disconnect: Blend Door Actuator C289. Key in ON position. Measure the voltage between blend door actuator C289 pin 7, circuit 439 (PK/BK) and ground. H2 GO to H2. REPAIR circuit 439 (PK/BK). TEST the Is the voltage greater than 10 volts? system for normal operation. CHECK THE GROUND TO THE BLEND DOOR ACTUATOR

412-00-38 Climate Control System - General Information 412-00-38 DIAGNOSIS AND TESTING PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H2 CHECK THE GROUND TO THE BLEND DOOR ACTUATOR Measure the resistance between blend door actuator C289 pin 8, circuit 57 (BK) and ground. H3 GO to H3. REPAIR circuit 57 (BK). TEST the system Is the resistance less than 5 ohms? for normal operation. CHECK THE TEMPERATURE CONTROL LOW SIDE OPERATION Measure the resistance between blend door actuator C289 pin 4, circuit 438 (RD/WH) and pin 3, circuit 437 (YE/LG) while rotating the temperature control switch from full WARM to full COOL. H4 GO to H6. Does the resistance vary from 150 ohms to 4,700 ohms? GO to H4. CHECK CIRCUIT 438 (RD/WH) FOR AN OPEN Disconnect: Temperature Control Switch C294d.

412-00-39 Climate Control System - General Information 412-00-39 DIAGNOSIS AND TESTING PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H4 CHECK CIRCUIT 438 (RD/WH) FOR AN OPEN Measure the resistance between temperature control switch C294d pin 1, circuit 438 (RD/WH), and blend door actuator C289 pin 4, circuit 438 (RD/WH). H5 GO to H5. REPAIR circuit 438 (RD/WH). TEST the Is the resistance less than 5 ohms? system for normal operation. CHECK CIRCUIT 437 (YE/LG) FOR AN OPEN Measure the resistance between temperature control switch C294d pin 2, circuit 437 (YE/LG), and blend door actuator C289 pin 3, circuit 437 (YE/LG). INSTALL a new temperature control switch. REFER to Section 412-04. TEST the system for normal operation. REPAIR circuit 437 (YE/LG). TEST the Is the resistance less than 5 ohms? system for normal operation.

412-00-40 Climate Control System - General Information 412-00-40 DIAGNOSIS AND TESTING PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H6 CHECK THE TEMPERATURE CONTROL HIGH SIDE OPERATION Measure the resistance between blend door actuator C289 pin 6, circuit 436 (RD/LG) and pin 3, circuit 437 (YE/LG) while rotating the temperature control switch from full WARM to full COOL. H7 GO to H8. Does the resistance vary from 150 ohms to 4,700 ohms? GO to H7. CHECK CIRCUIT 436 (RD/LG) FOR AN OPEN Disconnect: Temperature Control Switch C294d. Measure the resistance between temperature control switch C294d pin 3, circuit 436 (RD/LG), and blend door actuator C289 pin 4, circuit 436 (RD/LG). H8 INSTALL a new temperature control switch. REFER to Section 412-04. TEST the system for normal operation. REPAIR circuit 436 (RD/LG). TEST the Is the resistance less than 5 ohms? system for normal operation. CHECK CIRCUIT 438 (RD/WH) FOR A SHORT TO GROUND Disconnect: Temperature Control Switch C294d.

412-00-41 Climate Control System - General Information 412-00-41 DIAGNOSIS AND TESTING PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H8 CHECK CIRCUIT 438 (RD/WH) FOR A SHORT TO GROUND Measure the resistance between temperature control switch C294d pin 3, circuit 438 (RD/WH), and ground. H9 GO to H9. REPAIR circuit 438 (RD/WH). TEST the Is the resistance greater than 10,000 ohms? system for normal operation. CHECK CIRCUIT 437 (YE/LG) FOR A SHORT TO GROUND Measure the resistance between temperature control switch C294d pin 2, circuit 437 (YE/LG), and ground. H10 GO to H10. REPAIR circuit 437 (YE/LG). TEST the Is the resistance greater than 10,000 ohms? system for normal operation. CHECK CIRCUIT 436 (RD/LG) FOR A SHORT TO GROUND Measure the resistance between temperature control switch C294d pin 1, circuit 436 (RD/LG), and ground. GO to H11. REPAIR circuit 436 (RD/LG). TEST the Is the resistance greater than 10,000 ohms? system for normal operation.

412-00-42 Climate Control System - General Information 412-00-42 DIAGNOSIS AND TESTING PINPOINT TEST H: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY H11 CHECK FOR A BINDING, STUCK OR BROKEN BLEND DOOR Remove the blend door actuator. Inspect for a binding, stuck or broken blend door or linkage. REPAIR the blend door/linkage. TEST the Is there a binding, stuck or broken blend door or linkage system for normal operation. condition? INSTALL a new temperature blend door actuator. TEST the system for normal operation. PINPOINT TEST I: THE BLOWER MOTOR IS INOPERATIVE I1 CHECK CIRCUIT 261 (OG/BK) Disconnect: Blower Motor C1227. Turn the blower motor switch to the HIGH position. Measure the resistance between A/C blower motor C1227, circuit 261 (OG/BK) and ground. I2 GO to I4. Is the resistance less than 5 ohms? GO to I2. CHECK CIRCUIT 261 (OG/BK) Disconnect: Blower Motor Switch C294b. Measure the resistance between blower motor switch C294b, circuit 261 (OG/BK) and blower motor C1227, circuit 261 (OG/BK). GO to I3. REPAIR circuit 261 (OG/BK). TEST the Is the resistance less than 5 ohms? system for normal operation.

412-00-43 Climate Control System - General Information 412-00-43 DIAGNOSIS AND TESTING I3 PINPOINT TEST I: THE BLOWER MOTOR IS INOPERATIVE CHECK CIRCUIT 57 (BK) Measure the resistance between blower motor switch C294ba, circuit 57 (BK) and ground. I4 INSTALL a new blower motor switch. REFER to Section 412-04. TEST the system for normal operation. REPAIR circuit 57 (BK). TEST the system Is the resistance less than 5 ohms? for normal operation. CHECK A/C BLOWER MOTOR CIRCUIT 515 (OG/RD) FOR VOLTAGE Key in ON position. Measure the voltage between A/C blower motor C1227, circuit 515 (OG/RD) and ground. I5 INSTALL a new blower motor. REFER to Section 412-04. TEST the system for normal operation. Is the voltage greater than 10 volts? GO to I5. CHECK CIRCUIT 515 (OG/RD) Disconnect: Blower Motor Relay. Measure the resistance between the blower motor relay connector pin 87, circuit 515 (OG/RD) and blower motor C1227, circuit 515 (OG/RD). GO to I6. REPAIR circuit 515 (OG/RD). TEST the Is the resistance less than 5 ohms? system for normal operation.

412-00-44 Climate Control System - General Information 412-00-44 DIAGNOSIS AND TESTING I6 PINPOINT TEST I: THE BLOWER MOTOR IS INOPERATIVE CHECK THE BLOWER MOTOR RELAY Connect: Blower Motor C1227. Key in ON position. Connect a fused jumper lead between the blower motor relay socket pin 30 and pin 87, circuit 515 (OG/RD). I7 GO to I7. REPAIR circuit 364 (BK/LG). TEST the Does the blower motor operate? system for normal operation. CHECK CIRCUIT 57 (BK) Measure the resistance between the blower motor relay socket pin 86, circuit 57 (BK) and ground. I8 GO to I8. REPAIR circuit 57 (BK). TEST the system Is the resistance less than 5 ohms? for normal operation. CHECK THE BLOWER MOTOR RELAY Key in ON position. Measure the voltage between the blower motor relay socket pin 85, circuit 753 (YE/RD) and socket pin 86, circuit 57 (BK). INSTALL a new blower motor relay. TEST the system for normal operation. Is the voltage greater than 10 volts? GO to I9.

412-00-45 Climate Control System - General Information 412-00-45 DIAGNOSIS AND TESTING I9 PINPOINT TEST I: THE BLOWER MOTOR IS INOPERATIVE CHECK CIRCUIT 753 (YE/RD) Measure the resistance between blower motor relay connector pin 85, circuit 753 (YE/RD) and function selector switch C294a-3, circuit 753 (YE/RD). I10 GO to I10. REPAIR circuit 753 (YE/RD). TEST the Is the resistance less than 5 ohms? system for normal operation. CHECK CIRCUIT 489 (PK/BK) FOR VOLTAGE Key in ON position. Measure the voltage between blower motor switch C294b, circuit 489 (PK/BK) and ground. INSTALL a new function selector switch. REFER to Section 412-04. TEST the system for normal operation. REPAIR circuit 489 (PK/BK). TEST the Is the voltage greater than 10 volts? system for normal operation. PINPOINT TEST J: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY J1 J2 CHECK THE BLOWER MOTOR OPERATION Key in ON position. Turn the function selector switch to the FLOOR position. If the blower motor does not operate in HI, Select all blower speed positions. GO to J2. Does the blower motor operate in any position? If the blower motor does not operate in MED-HI, GO to J3. If the blower motor does not operate in MED-LO, GO to J4. If the blower motor does not operate in LO, GO to J5. For all other symptoms, GO to J9. GO to Pinpoint Test I. CHECK CIRCUIT 261 (OG/BK) Disconnect: Blower Motor Switch C294b. Disconnect: Blower Motor C1227.