HEATER LOW/NO HEAT WHEN TEMPERATURE Article No. KNOB IS SET AT FULL HEAT 94-20-16 FORD: 1992-1994 BRONCO, F-150-350 SERIES ISSUE Some vehicles may exhibit a low or no heat condition when the temperature knob is set to the full heat position. This may be caused by the temperature door cable not closing the temperature door fully. ACTION Adjust the existing cable to obtain full door closure. If the cable cannot be adjusted sufficiently to obtain full door closure, replace the temperature control cable. Refer to the following for repair procedures. DIAGNOSTIC PROCEDURE 1. With a low/no heat condition, diagnosis should always begin with a check of the vehicle s coolant to be sure it is at the proper level, concentration and operating temperature with the thermostat open. If it is below specification, it should be corrected first. c. On 1992-93 F-Series/Bronco: If low/no heat condition still exists, disconnect the cable at the plenum and wire the door shut in the full warm position. With the engine still running, set the blower speed on High and place the mode selector on Floor. Check for proper temperature and discharge air volume at the floor duct. If the low/no heat condition still exists and the coolant temperature is still in specifications, the concern could be blockage in the duct work or plenum, air leakage which chills off the air after it goes through the heater core, or possibly a defective plenum. Further diagnosis is required. d. If wiring the door shut in the full heat position resolves the issue, the problem is most likely in the cable and a new cable should be installed. For proper procedures, refer to Service Procedure which follows. 2. Bring the vehicle to normal operating SERVICE PROCEDURE temperature. a. On 1994 F-Series/Bronco: If low/no heat ADJUSTMENT PROCEDURE condition still exists, replace the temperature 1. Open the glove box to gain access to the door control cable. For proper procedures, adjustment clip. refer to the Service Procedure which follows. 2. Pull back on the white tab on the adjustment as b. On 1992-93 F-Series/Bronco: If low/no heat shown in Figure 4. condition still exists, perform the control 3. With the tab held back, move the barrel that cable adjustment procedure as outlined in travels through the clip in the direction required the Service Procedure which follows. to obtain the proper door seating. Move the barrel one notch and verify that the door seats in each direction of travel. NOTE DO NOT MOVE THE BARREL MORE THAN TWO (2) NOTCHES FROM THE CENTER POSITION IN EITHER DIRECTION. MOVING THE BARREL MORE THAN TWO (2) NOTCHES MAY RESULT IN BARREL DETACHMENT FROM THE CLIP DURING LATER OPERATION OF THE TEMPERATURE CONTROL. PROOF 19-MAY-00 CCD94014 CCD94014 PAGE 1
4. On 1992 vehicles, follow Steps 1, 2 and 3. LEFT HAND AREA OF THE HEATER CORE However, in Step 3, if more than two (2) ACCESS COVER. THE CLIP IS RETAINED BY notches of travel are required, check the cable TWO (2) TABS. THE HEATER-A/C and cam for binding. If there is no binding TEMPERATURE CABLE CLIP REMOVER present, replace the temperature control cable (D91T-18532-A, OR EQUIVALENT) IS REQUIRED (F4TZ-18518-A), the temperature control cam TO DEPRESS THE LOCKING TABS IN ORDER (F3TZ-19788-A) and the heater access cover TO ALLOW FOR REMOVAL FROM THE (F3TZ-18B299-A). ATTACHING BRACKET. 5. After attaching the cable and clip, make 1. Open the glove box door to gain access to the adjustments to the clip and verify that the adjustment clip. temperature door closes at both ends of travel. 2. Position the removal tool over the bracket and 6. On 1993 vehicles, follow Steps 1, 2 and 3. If in clip as shown in Figure 3. Step 3, more than two (2) notches of travel are required, check the temperature control cam for 3. Align the opening in the removal tool with the binding. Cam binding can be checked by retaining tabs which project through the bracket detaching the cable from the cam and actuating and pull back firmly (when properly aligned the cam by hand. The cam should move freely. against the bracket, the tool handle will be If it is binding, adjust it to eliminate the binding. horizontal but angled slightly downward). This Reattach the cable and verify that the will depress the locking tab but not disengage temperature door closes at both ends of its the clip from the bracket. travel. If the temperature door does not close 4. While maintaining the pull on the tool, pull the properly, replace the temperature control cable clip away from the bracket with the free hand. using (F4TZ-18518-A), adjust if necessary and verify that the door closes properly. If the door 5. Examine the adjustment clip for damage during still does not close properly, the problem is removal. If one (1) or both tabs are broken or most likely in the control assembly. no longer spread away from the body of the a. Continue by removing the control assembly. clip, replace the clip (F1TZ-14A163-D). Detach the cable from the control assembly. 6. Disengage the cable wire from the temperature b. Check the travel of the rack when the door cam pin. Refer to Figure 1. temperature knob is rotated to the full cold 7. Refer to the appropriate Service Manual to position. The notch in the rack should stop remove the A/C Heater Control Assembly. at the bullet connector bracket when rotated to cold. Refer to Figure 5. If it does not 8. Disengage the cable connector and wire from come within 1mm or touch the bracket, the temperature door cam pin. replace the control assembly 9. If the temperature door control cam is being (F2TZ-19980-A). replaced, it should be removed at this time. c. Reattach the cable and verify that the door Refer to Figure 2. closes at both ends of its travel. 10. If the heater core access cover is being 7. On 1994 vehicles, verify that the temperature replaced, it should be removed at this time. door closes at both ends of its travel. If the Refer to Figure 2. door does not close properly, replace the temperature control cable (F4TZ-18518-A). CABLE INSTALLATION a. Adjust the cable if necessary and verify that 1. Attach the new temperature door control cam the door operates properly. (F3TZ-19788-A) if it is being replaced. DO NOT OVER TORQUE. Minimum torque is 0.7 N m (6 CABLE REMOVAL in-lb) and maximum torque is 1.7 N m (15 in-lb). Check for binding or too much movement NOTE effort and adjust if necessary. THE ADJUSTMENT CLIP IS ATTACHED TO A MOLDED-IN BRACKET LOCATED IN THE UPPER PAGE 2 CCD94014 CCD94014 PROOF 19-MAY-00
2. Install the heater core access cover OTHER APPLICABLE ARTICLES: 91-19-10 (F3TZ-18B299-A) if it is being replaced. WARRANTY STATUS: Eligible Under The Provisions Of Bumper To 3. Install the A/C-Heater Control Assembly if it is Bumper Warranty Coverage being replaced. Refer to the appropriate Service OPERATION DESCRIPTION TIME Manual for installation procedures. 942016A Replace Temperature 0.6 Hr. 4. On the adjustment clip at the cable end, move Control Cable - 1994 the barrel so the red insert is on center and Models Only the red does not show out from either end. 942016B Adjust Temperature 0.3 Hr. Further adjustment is not normally required, but Control Cable Only - can be made after installation, if necessary. 1992-93 Models Only 942016C Adjust Temperature 1.0 Hr. 5. Attach the cable to the control assembly if not Control Cable And Replace already attached in Step 3. Cam And Cover - 1992 Models Only 6. Attach the wire coil end to the temperature 942016D Adjust Temperature 0.8 Hr. control cam. Be sure the cable is under the Control Cable And Replace cable retainer. Refer to Figure 1. Control Assembly - 1993 7. Align the adjustment clip with the opening in Models Only the molded-in bracket as shown in Figure 3. DEALER CODING CONDITION 8. Push the clip firmly into place and ensure that BASIC PART NO. CODE both tabs hold the clip to the bracket (an 18518 08 audible click should be heard on engagement). OASIS CODES: 208000, 208100, 208999 Pull firmly on the clip to verify proper retention of the clip. 9. Rotate the temperature control to make sure the temperature door closes at both ends. PART NUMBER F4TZ-18518-A F3TZ-19788-A F3TZ-18B299-A F2TZ-19980-A F1TZ-14A163-D PART NAME Temperature Control Cable Temperature Control Cam Heater Access Cover Heater Control Assembly Clip PROOF 19-MAY-00 CCD94014 CCD94014 PAGE 3
Figure 1 - Article 94-20-16 Figure 2 - Article 94-20-16 PAGE 4 CCD94014 CCD94014 PROOF 19-MAY-00
Figure 3 - Article 94-20-16 Figure 4 - Article 94-20-16 PROOF 19-MAY-00 CCD94014 CCD94014 PAGE 5
Figure 5 - Article 94-20-16 PAGE 6 CCD94014 CCD94014 PROOF 19-MAY-00