Section 35 Chapter 9

Section 35 Chapter 9 HITCH SYSTEM How it Works 6-12820NH

TABLE OF CONTENTS THREE POINT HITCH... 35-3 ELECTRONIC HITCH CONTROL... 35-4 ELECTRONIC HITCH CONTROL... 35-5 ELECTRONIC HITCH CONTROL SYSTEM FEATURES... 35-7 HITCH CONTROL VALVE... 35-14 General... 35-14 Raise and Lower Solenoids... 35-14 Raise and Lower Pilot Spools... 35-14 Raise Spool... 35-14 Lower Poppet... 35-14 Load Check Ball... 35-14 Manual Raise or Lower Control Pins... 35-14 Overload Relief Valve... 35-14 HITCH CONTROL VALVE... 35-16 Neutral Function and Troubleshooting... 35-16 Raise Function and Troubleshooting... 35-18 Lower Function and Troubleshooting... 35-20 SETUP / ADJUSTMENT SEQUENCE... 35-22 35-2

THREE POINT HITCH GENERAL DESCRIPTION - The Three Point Hitch consists of the rockshaft supports, rockshaft, upper link, lift links, draft arms and the external lift cylinders. The hitch conforms to ASAE standard dimensions for a Category III/IIIN hitch. The hitch is controlled with an electronic hitch system which provides position control of soil engaging implements. The hitch will accept all mounted implements conforming to SAE, ASAE standard dimensions for Category III/IIIN. A hitch coupler can be used with the three point hitch to quickly connect and disconnect implements. See the operator manual for proper hitch preparation. The single acting hydraulic cylinders are mounted externally and are supplied from the hitch control valve. The hitch control valve is mounted on the left hand side of remote valve stack (rear/top of the transmission). The electro-hydraulic control valve is supplied from the PFC hydraulic system and the regulated system. The regulated supply is used to operate the valve and the PFC supply provides the high pressure flow to extend the cylinders and raise the hitch. To lower the hitch regulated pressure is used to operate the valve to lower the hitch without activating the PFC system. Two electrical solenoids control the regulated oil supply to the valve, one to control the raise and one to control hitch lower. The Electronic Hitch Controller supplies current to the raise or lower solenoids based on commands from the operator and measurement signals from the hitch and other tractor systems. 4 1 2 5 5 2 3 1. UPPER LINK 4. ROCKSHAFT ASSEMBLY 2. LIFT LINKS 5. EXTERNAL LIFT CYLINDERS 3. DRAFT ARMS RP98G006 35-3

ELECTRONIC HITCH CONTROL GENERAL DESCRIPTION - The Electronic Hitch Control (EHC) system consists of the operator controls, electronic hitch controller, hitch position sensor, hitch control valve and the wiring harness. All operator commands except Remote Up/Down commands are sent to the Arm Rest Control Unit then relayed to the Hitch controller by way of the Data Bus. The Remote Up/Down commands are sent to the EHC controller direct as well as the Rockshaft Position Sensor signals. Wheel speed and optional True Ground speed signals are sent to the Instrument Cluster Unit (ICU) then relayed to the Hitch controller. Diagnostic and programming information are communicated between the EHC controller and the Instrument Control Unit (ICU) by way of the Data Bus. OPERATING MODES - The EHC system operates in three modes based on operator commands and measurement signals from the hitch and other systems. 1. Position Control 2. Load Control 3. Slip Control (Optional with True Ground Speed) END-OF-ROW FEATURE - The EHC will also engage and disengage the differential lock and the MFD (When equipped) when the hitch is raised at the end of the row to facilitate turning and re-engage when the hitch is lowered. 35-4

ELECTRONIC HITCH CONTROL RH98F144 35-5

ELECTRONIC HITCH CONTROL POSITION CONTROL - In the Position Control Mode the hitch position and movement is directly related to the position of the control lever. The EHC monitors the position of the hitch by signals received from a hitch position sensor on the hitch rockshaft and raises or lowers the hitch to match the signal from the hitch position control lever sensor. The hitch will always raise at maximum speed to a height set by the operator with the upper limit control. During lowering, the hitch moves at the speed selected by the Drop Speed Control to a position set by the operator with the Position Control. The operator can override the Drop Rate setting when lowering the hitch by activating the Up/Down switch to the down momentary position 2 times within 2 seconds and holding it in the momentary position. The hitch will lower at maximum rate. In this case the hitch will lower to the lowest possible position, even if this is below the position command. LOAD CONTROL - In the Load Control Mode the EHC maintains a constant draft load on the tractors three point hitch in changing soil conditions. When an increase in load is sensed by the lower link draft pins the EHC will raise the hitch until the load matches the load set by the operator with the Load Control. With a decrease in load the EHC will lower the hitch to a depth the operator has set with the Position Control. SLIP LIMIT CONTROL - The slip limit control mode is available when the tractor is equipped with True Ground Speed (Radar) attachment. The Instrument Cluster Unit receives measurement signals from the True Ground Speed unit and the Wheel Speed sensor to determine the actual slip percentage. The percent of slippage is relayed to the EHC by way of the Data Bus. The operator can set a desired slip limit range between 5 and 40% which the EHC compares to the actual slippage signal from the Instrument Cluster Unit and raises the hitch when the slip limit is exceeded. When the actual slip no longer exceeds the slip limit, the hitch will lower to the position command setting. The tractor must be travelling above 2 mph before the EHC will enter slip limit. 35-6

ELECTRONIC HITCH CONTROL SYSTEM FEATURES HITCH POSITION CONTROL LEVER - The Position Control Lever (2) is used to raise and lower implements, and select the maximum working depth of the implement. To lift an implement with the three point hitch the Position Control Lever (2) is rotated forward (clockwise). To lower an implement, rotate the lever rearward (Counterclockwise). The Lower Limit Stop (3) can be adjusted to provide a lever stop which will enable the Position Control Lever to return to the same set position and set the maximum implement depth. HITCH LOAD CONTROL - The hitch load control knob (10) sets the depth of the implement to control the load on the tractor. Turn the knob clockwise to increase the load on the tractor by lowering the implement. Turn the knob counterclockwise to decrease the load on the tractor by raising the implement. The Transport Lock (5) is a detent device molded into the arm rest control console. The Position Control Lever can be locked in the raise position to prevent the lowering of raised implements during transport. This can be done by pushing the Position Control Lever all the way forward (clockwise) and snapping it into the detent position. As an added precaution the Up/Down Switch should also be in the UP position. UP/DOWN SWITCH - The Up/Down Switch (1) is a three position switch used to raise and lower the hitch without changing any of the hitch adjustments. The three positions of the switch are: UP; DOWN (Middle) and MOMENTARY (Full forward). When the switch is put in the UP position the hitch will raise at maximum speed to the position set by the Upper Limit Control. When the switch is put in the DOWN position the hitch will lower to the limit set by the Position Control Lever at the speed set by the Drop Speed Control. When the switch is pushed into the MOMENTARY position and released, pushed again and held (Within 2 seconds), the hitch will lower to the lowest possible position at maximum speed (Bypassing the Drop Rate Speed setting and position control lever). The switch can also be used to raise and lower the hitch at a timed momentary rate in case a system malfunction creates a Limp Mode condition (Electronic system not functioning). The MOMENTARY position will allow a timed (1.5 seconds) lowering of the hitch when in the Limp Mode. When the hitch is in the Limp Mode toggling the switch between the UP and DOWN positions will allow a timed raise (1.5 seconds) of the hitch. 35-7

ELECTRONIC HITCH CONTROL 5 2 1 10 3 4 6 7 9 8 1. UP/ DOWN SWITCH 6. SLIP LIMIT CONTROL SWITCH 2. HITCH POSITION CONTROL LEVER 7. UPPER LIMIT CONTROL 3. LOWER LIMIT STOP 8. DROP SPEED CONTROL 4. LOWER LIMIT LOCK 9. TRAVEL CONTROL 5. TRANSPORT LOCK 10. HITCH LOAD CONTROL RH02G120 AND RH01K052 35-8

ELECTRONIC HITCH CONTROL SYSTEM FEATURES UPPER LIMIT CONTROL - The Upper Limit Control (7) limits the amount of upward travel when the hitch is raised. The control knob is mounted under the arm rest cover on the arm rest control console and has number settings from 1 to 11. Turning the knob counterclockwise limits the upward travel of the hitch and turning clockwise allows the hitch to raise further. A setting of 11 will allow the hitch to raise to the Full Up position. A setting of 1 will allow the hitch to raise to approximately 50% of full travel. The UPPER LIMIT CONTROL allows the operator to tailor the upward hitch travel to specific implements or mounted PTO implements. DROP SPEED CONTROL - The Drop Speed Control (8) limits the hitch lowering speed. The control is located under the arm rest control cover on the arm rest control console. Turning the knob counterclockwise causes the hitch to lower slower. The Drop Speed should be adjusted slower for specific implements such as planters, to prevent seed tube plugging. A faster speed would be used for plows and rippers. REMOTE UP/DOWN SWITCHES - The REMOTE UP/DOWN SWITCHES are located on the rear of the tractor mounted next to the implement electrical outlet. The switches are used to operate the hitch momentarily from outside the cab to make small slow movements to the hitch to aid in attaching implements to the hitch. The switches will only be active if the tractor is not moving. The hitch cannot be raised above the upper limit. After the hitch is moved with the remote switches it may be necessary the recapture the hitch with the Position Control Lever when the operator returns to normal operation. LOAD CONTROL - The LOAD CONTROL KNOB (10) is located on the arm rest control console and is used to set draft load on the three point hitch. The EHC receives a load signal from the lower link draft pins and adjusts the depth of implement to match the draft load signal set by the operator with the LOAD CONTROL KNOB. The tractor must be moving 0.5 mph or faster before the Load Control Mode will activate. Turning the LOAD CONTROL KNOB clockwise will increase the load and counterclockwise will decrease the load. Load Control Mode will be shut off when the LOAD CONTROL KNOB is turned to position 11. 35-9

ELECTRONIC HITCH CONTROL SYSTEM FEATURES 5 2 1 10 3 4 6 7 9 8 1. UP/ DOWN SWITCH 6. SLIP LIMIT CONTROL SWITCH 2. HITCH POSITION CONTROL LEVER 7. UPPER LIMIT CONTROL 3. LOWER LIMIT STOP 8. DROP SPEED CONTROL 4. LOWER LIMIT LOCK 9. TRAVEL CONTROL 5. TRANSPORT LOCK 10. HITCH LOAD CONTROL RH02G120 AND RH01K052 35-10

ELECTRONIC HITCH CONTROL SYSTEM FEATURES TRAVEL CONTROL KNOB - The TRAVEL CONTROL KNOB (9) is located under the arm rest control console cover. Travel Control varies the range of hitch corrections in response to load variations when operating in the LOAD CONTROL MODE. Turning the TRAVEL CONTROL clockwise to a higher setting will result in larger amounts of hitch movement in response to a load change and a closer control of the load when operating on uneven terrain. Turning the TRAVEL CONTROL counterclockwise will result in less hitch movement in response to a load change and increase the variations in load which would be used in level ground conditions. 2. Manually Increase Set Point - Press the switch to the SET position and release. Each time the switch is pressed the Slip Limit Setting will increase 1%. 3. Manually Decrease Set Point - Move the switch to the OFF position then back to the ON position quickly (one second or less) the Slip Limit Setting will be decreased 1% each time the switch is cycled. NOTE: The slip limit control switch is not functional unless the tractor is moving faster than 2 mph. SLIP LIMIT CONTROL SWITCH - The SLIP LIMIT CONTROL SWITCH (6) (If equipped) is located on the arm rest control console and is used to engage or disengage slip control and set the desired slip limit. The slip control rocker switch has three positions: 1. OFF - Symbol (O) this position is used to turn SLIP CONTROL OFF and it is also used to decrease the slip limit setting. 2. ON - Symbol (I) in this position, the system will operate in the Slip Limit Control Mode. If no limit has been set the system will default to 30%. 3. SET (Momentary) This position is used to set the slip limit. To set the SLIP LIMIT the tractor must be properly ballasted for the load being pulled and moving over 2 MPH with the hitch set for the desired implement load or position. Move the Slip Limit Control Switch to the ON (middle) position, then press the SET (momentary) and release. The performance monitor screen on the Instrument Cluster will display. The triangle indicator under the bar graph will indicate slip limit value, which will be the current slip + 5%. The system will not set below 5% or above 40%. The EHC will raise the hitch if wheel slip exceeds the limit value. The SLIP LIMIT can be changed three ways to match field conditions: 1. Reset system - Move the switch to the OFF position for at least two seconds then reset by moving the switch to ON then to SET and release. 35-11

ELECTRONIC HITCH CONTROL SYSTEM FEATURES 5 2 1 10 3 4 6 7 9 8 1. UP/ DOWN SWITCH 7. UPPER LIMIT CONTROL 2. HITCH POSITION CONTROL LEVER 8. DROP SPEED CONTROL 3. LOWER LIMIT STOP 9. TRAVEL CONTROL 4. LOWER LIMIT LOCK 10. HITCH LOAD CONTROL 5. TRANSPORT LOCK 11. MFD SWITCH 6. SLIP LIMIT CONTROL SWITCH 12. DIFFERENTIAL LOCK SWITCH RH02G120 AND RH01K052 35-12

EHC SYSTEM FEATURES END OF ROW FUNCTION - The END OF ROW feature involves the Differential Lock and the Mechanical Front Drive (MFD) (if equipped) and the Brake Switches. The MFD and Diff Lock control systems are equipped with an automatic function that disengages both Diff Lock and MFD when the hitch is raised for a turn around and re-engages them when the hitch is lowered after the turn. DIFFERENTIAL LOCK SWITCH - The Differential Lock Switch (12) has three positions; 1. SET (differential symbol) - Push full forward (Momentary) to engage Differential Lock in the manual mode. 2. Center Position - Latch position for manual mode and Reset position for Automatic mode. 3. Automatic (A) - Provides automatic operation. The Diff Lock will disengage when: A. Travel speed exceeds 10 MPH B. One or both brakes are applied and held on The Diff Lock will engage or reengage: A. One or Both brakes are released B. Wheel Slip exceeds 10% (If equipped with Radar) MFD SWITCH - The MFD Switch (11) has three positions; 1. ON - (MFD symbol) 2. AUTOMATIC - (A) 3. OFF - (O) ISO Symbol AUTOMATIC MODE FUNCTION - When the MFD and Diff Lock are in the automatic mode and the hitch is raised to the upper third of travel they will disengage and reengage when the hitch is lowered below the upper third of travel. The automatic mode of operation of the MFD also provides these additional features: The MFD will disengage when: A. Travel speed exceeds 10 MPH B. One brake is applied The MFD will engage or reengage when: A. One brake is released B. Both brakes are applied C. Wheel Slip exceeds 10% (If equipped with Radar) D. Travel speed drops below 8 MPH after travel above 10 MPH E. Differential Lock is applied The automatic mode of operation of the Diff Lock also provides these additional features: 35-13

HITCH CONTROL VALVE General The hitch control valve is a closed center valve that receives oil from the PFC hydraulic system. To control the pump during hitch operations signal pressure is sent from the valve to the PFC pump. The raise and lower functions of the valve are operated by regulated pressure received from the regulated hydraulic system. The valve is mounted in the remote valve stack and consists of the following components: Raise and Lower Solenoids The raise and lower solenoids (1 and 2), when energized by the Electronic Hitch Controller, will move the raise and lower pilot spools (3 and 4) inward through contact with the control pins (14). Manual Raise or Lower Control Pins The raise and lower solenoid each contain a pin (14) in the center of the outer end that can be used to manually activate the raise spool and lower control piston. Overload Relief Valve The overload relief valve (6) will allow oil from the raise/lower port to flow into the pilot chamber of the lower control piston (7). The piston moves to the right and pulls the lower pilot poppet (8) off its seat when the hitch sees an overload. Raise and Lower Pilot Spools The raise and lower pilot spools (3 and 4) control the amount of regulated oil pressure allowed to pass the spool lands to operate the raise spool (5) and lower control piston (7). Raise Spool The raise spool (5) is held in position by a spring which blocks the flow of oil from the PFC pump. Regulated pressure from the raise pilot spool (3) will move the spool against spring force, which will open the PFC pump port and expose PFC pump pressure to the load check ball (10) and the signal port. Lower Poppet The lower poppet (9), lower pilot poppet (8) and spring (15) trap oil in the hitch cylinder circuit. The lower pilot poppet (8) is held on its seat by a spring (15) and cylinder circuit pressure, which is allowed to get to the back side of the spool through an orifice (16) in the poppet. Load Check Ball The load check ball (10) traps oil in the hitch cylinder circuit to hold the hitch in a raised position. The ball is unseated when PFC pump pressure exposed to the ball by the raise spool over comes the pressure in the hitch cylinder circuit. 35-14

HITCH CONTROL VALVE 16 18 9 15 8 7 17 10 6 1 3 4 2 14 12 13 11 5 13 12 14 1. RAISE SOLENOID 10. LOAD CHECK BALL 2. LOWER SOLENOID 11. PFC PUMP SUPPLY 3. RAISE PILOT SPOOL 12. REGULATED PRESSURE SUPPLY 4. LOWER PILOT SPOOL 13. RETURN PORT 5. RAISE SPOOL 14. CONTROL PIN 6. OVERLOAD RELIEF 15. SPRING 7. LOWER CONTROL PISTON 16. ORIFICE 8. LOWER PILOT POPPET 17. TANK PORT 9. LOWER POPPET 18. RAISE/LOWER PORT RI02B003 35-15

HITCH CONTROL VALVE Neutral Function and Troubleshooting Function Hitch Control Valve in Neutral - The hitch control valve is a closed-center valve. In neutral there will be no electric current supplied to the raise or lower solenoids (1 and 2) and no oil flow through the valve. The pilot spools (3 and 4) are blocking the supply of oil from the regulated circuit. The raise spool (5) is blocking the supply of oil from the PFC system and is held in place by a spring. The lower poppet (9), lower pilot poppet (8) and the load check ball (10) are blocking the return of oil from the hitch cylinder circuit. The overload relief (6) also blocks the return of oil from the hitch cylinder circuit. The lower poppet (9) is held on the seat by a spring (15) and the oil trapped behind the poppet by the lower pilot poppet (8). Pressure from the hitch cylinder circuit gets behind the lower poppet through an orifice (16) in the side of the poppet. A. Check load check ball (10) and seat if seat is damaged replace the hitch valve. B. Check the lower poppet (9) and seat, lower pilot poppet (8) and seat. If any components are damaged repair or replace as necessary. C. Check overload relief assembly (6) and seat. If any components are damaged repair or replace as necessary. Troubleshooting Problem - Hitch will not hold position or leaks down. 1. Check the function of other systems (Transmission, Remote Valves), A. If the other systems do not function properly refer to troubleshooting of the non functioning system. B. If other systems function properly go to step 2. 2. Check for HITCH fault codes. A. If fault codes are found, follow procedures outlined in HITCH fault code troubleshooting in this section. B. If no fault codes are found go to step 3. 3. With a load on the hitch, raise the hitch to maximum height and disconnect the hitch cylinder drain line from the rear frame housing. A. If oil flows from the drain line as the hitch settles the cylinder(s) is/are leaking internally. Repair cylinders as needed. B. If no oil flows from the drain line go to step 4. 4. Check and repair the hitch valve as needed. 35-16

HITCH CONTROL VALVE - NEUTRAL 16 18 9 15 8 7 17 10 6 1 3 4 2 14 12 13 11 5 13 12 14 RI02B003 1. RAISE SOLENOID 10. LOAD CHECK BALL 2. LOWER SOLENOID 11. PFC PUMP SUPPLY 3. RAISE PILOT SPOOL 12. REGULATED PRESSURE SUPPLY 4. LOWER PILOT SPOOL 13. RETURN PORT 5. RAISE SPOOL 14. CONTROL PIN 6. OVERLOAD RELIEF 15. SPRING 7. LOWER CONTROL PISTON 16. ORIFICE 8. LOWER PILOT POPPET 17. TANK PORT 9. LOWER POPPET 18. RAISE/LOWER PORT 35-17

HITCH CONTROL VALVE Raise Function and Troubleshooting Function Hitch Control Valve in Raise - To raise the hitch, the hitch raise solenoid (1) must be energized by the Electronic Hitch Controller. When the solenoid is energized the armature in the solenoid moves toward the valve contacting a control pin (14) which moves the raise pilot spool (3) inward. The amount of movement of the spool depends on the amount of current applied to the solenoid by the controller. The amount of current the controller applied to the solenoid depends on the command information the operator has sent to the controller. As the raise pilot spool (3) is shifted inward it meters regulated pressure from the regulated circuit (12) to the left hand side of raise spool (5). The metered regulated pressure shifts the raise spool against the spring, allowing oil from the PFC pump circuit (11) to flow past the spool land to the hitch load check ball (10) which is seated by pressure from the hitch cylinders created by the load on the cylinders. At the same time PFC standby pressure is sent through the signal port and signal check valve to the PFC pump compensator which will activate the pump to increase flow output. As pressure increases the load check ball is lifted off the seat allowing flow to the hitch cylinders. The hitch will stop raising when the controller shuts off current to the raise solenoid (1). Regulated pressure acting on the right hand end of the raise pilot spool will shift the pilot spool outward shutting off regulated pressure supply (12) and opening the return port (13) to release the pressure on the raise spool. The spring will shift the raise spool (5) shutting off the PFC inlet port. The pressure in the hitch cylinders will seat the hitch load check ball (10) trapping the oil. The signal pressure will bleed off through the orifice in the raise spool (5) and allow the pump to return to low pressure standby. Troubleshooting Problem - Hitch will not raise 1. Check the function of other systems (Transmission, Remote Valves). A. If other systems do not function properly refer to the troubleshooting section on the non functioning system. B. If other systems function properly go to step 2. 2. Check for HITCH fault codes A. If fault codes are present refer to fault code troubleshooting in this section. B. If no fault codes are present go to step 3. 3. Check for manual operation of the control valve by pushing in on the manual control pin (14) in the center of the outer end of the raise solenoid with a small punch or 1/8 inch rod. A. If the hitch raises, test hitch raise solenoid for proper electrical function and recheck HITCH fault codes. B. If the hitch does not raise refer to the Hydraulic Troubleshooting the PFC System and the regulated pressure system. If the hydraulic system functions properly go to step C. C. Check for free movement of the raise pilot spool (3) and raise spool (5). Repair or replace as necessary. 35-18

HITCH CONTROL VALVE Raise Function and Troubleshooting 16 18 9 15 8 7 17 10 6 1 3 4 2 14 12 13 11 5 13 12 14 1. RAISE SOLENOID 10. LOAD CHECK BALL 2. LOWER SOLENOID 11. PFC PUMP SUPPLY 3. RAISE PILOT SPOOL 12. REGULATED PRESSURE SUPPLY 4. LOWER PILOT SPOOL 13. RETURN PORT 5. RAISE SPOOL 14. CONTROL PIN 6. OVERLOAD RELIEF 15. SPRING 7. LOWER CONTROL PISTON 16. ORIFICE 8. LOWER PILOT POPPET 17. TANK PORT 9. LOWER POPPET 18. RAISE/LOWER PORT RI02B006 35-19

Lower Function and Troubleshooting HITCH CONTROL VALVE Function Hitch Valve in Lower - To lower the hitch, the lower solenoid (2) must be energized by the Electronic Hitch Controller based on the commands entered by the operator. Activation of the PFC system is not required to lower the hitch. When the lower solenoid (2) is energized the armature will move toward the valve contacting the control pin (14) which pushes the lower pilot spool (4) inward. The amount of movement depends on the amount of current that is sent to the solenoid by the Electronic Hitch Controller based on the commands to the controller by the operator. As the lower pilot spool (4) shifts it meters regulated pressure from the regulated pressure supply (12), through the overload relief, to the lower control piston (7). The piston moves to the right and pulls the lower pilot poppet (8) off its seat against spring (15) tension. Pressure escapes to tank creating a drop in pressure behind the lower poppet (9). The pressure in the raise/lower port now moves the lower poppet off the seat. The hitch can now lower as oil flows through to the tank port. The hitch will stop lowering when the solenoid (2) is de-energized. Oil pressure acting on the left end of the lower pilot spool (4) moves the spool outward closing the regulated pressure supply (12) to the lower control piston (7). As the pressure drops on the piston the pilot poppet (8) returns to its seat by spring force. With the pilot poppet port closed pressure from the hitch cylinders builds behind the lower poppet (9) through the orifice (16) forcing the poppet onto its seat trapping oil in the hitch cylinders. Troubleshooting Problem - Hitch will not lower 1. Check the function of other systems (Transmission, Remote valves). A. If other regulated pressure systems do not operate properly refer to troubleshooting of nonoperating system. B. If other systems operate properly go to step 2. 2. Check for HITCH fault codes. A. If fault codes are found refer to troubleshooting of any fault found. B. If no fault codes are found refer to step 3 3. Check for manual operation lower function by pushing in on the lower manual operating pin (14) in the center of the outer end of the lower solenoid with a small punch or 1/8 inch rod. A. If the hitch lowers, test hitch lower solenoid (2) for proper electrical function and recheck HITCH error codes. B. If hitch does not lower refer to Hydraulic Troubleshooting of the Regulated Pressure System. If the hydraulic system functions properly go to step C. C. Check the hitch control valve for free movement of the lower pilot spool (4),the lower poppet (9) and the lower control piston (7). Check condition of all o-ring seals and replace as necessary. 35-20

HITCH CONTROL VALVE Lower Function and Troubleshooting 16 18 9 15 8 7 17 10 6 1 3 4 2 14 12 13 11 5 13 12 14 1. RAISE SOLENOID 10. LOAD CHECK BALL 2. LOWER SOLENOID 11. PFC PUMP SUPPLY 3. RAISE PILOT SPOOL 12. REGULATED PRESSURE SUPPLY 4. LOWER PILOT SPOOL 13. RETURN PORT 5. RAISE SPOOL 14. CONTROL PIN 6. OVERLOAD RELIEF 15. SPRING 7. LOWER CONTROL PISTON 16. ORIFICE 8. LOWER PILOT POPPET 17. TANK PORT 9. LOWER POPPET 18. RAISE/LOWER PORT RI02B007 35-21

SETUP / ADJUSTMENT SEQUENCE SET POSITION CONTROL ABOUT 1 TO 2 INCHES BELOW DESIRED DEPTH TURN LOAD CONTROL CCW TO WHERE PLOW RAISES TO DESIRED DEPTH SURFACE DESIRED DEPTH SLIGHTLY BELOW POTENTIAL DEPTH MOVE POSITION CONTROL LEVER DEEPER THAN DESIRED DEPTH AS THE DRAFT LOAD VARIES, THE HITCH CONTROL WILL ADJUST THE DEPTH OF THE IMPLEMENT TO FINE TUNE TRAVEL, TURN THE TRAVEL CONTROL CCW TO LIMIT TRAVEL OPTIMUM OPERATING DEPTH VARIANCE 35-22