Grand Cherokee 2WD L6-4.0L VIN S (1997)
Power Seat Motor: Adjustments
Power Seat Adjuster and Motors
SYSTEM OPERATION
There are three reversible motors that operate the power seat adjuster. The motors are connected to worm-drive gearboxes that move the seat
adjuster through a combination of screw-type drive units.
The front and rear of a seat are operated by different motors. They can be raised or lowered independently of each other. When the seat switch is
pushed to the Up or Down position, both the front and rear motors operate in unison, moving the entire seat up or down. The forward-rearward
motor is operated by pushing the seat switch to its forward or rearward position.
When a switch is actuated, a battery feed and a ground path are applied through the switch contacts to the motor(s). The motor(s) operate to move
the seat in the selected direction until the switch is released, or until the travel limit of the power seat adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and ground paths to the motor(s) are reversed through the switch contacts. This causes the motor
to run in the opposite direction.
Each motor contains a self-resetting circuit breaker to protect it from overload. Consecutive or frequent resetting of the circuit breakers must not
be allowed to continue, or the motors may be damaged. Make the necessary repairs. The motors used on models with the optional memory system
also have a position potentiometer included in the motor assembly.
The power seat adjuster and motors cannot be repaired, and are serviced only as a complete unit. If any component in this unit is faulty or
damaged, the entire power seat adjuster and motors assembly must be replaced.
DIAGNOSIS AND TESTING
The tests below apply to a power seat system without the memory system option. For testing of the power seats with the memory system, refer to
the proper Computers and Control Systems/Body Control Module/Testing and Inspection Procedures.
Operate the power seat switch to move all three seat motors. The seat should move in each selected direction. If a motor fails to operate in only
one direction, move the seat a short distance in the opposite direction and test again to be certain the adjuster is not at its travel limit. If one or
more of the motors operate, see the diagnosis for the Power Seat Switch. If no motors operate, proceed as follows:
1. Test the circuit breaker in the junction block as described. If OK, go to Step 2. If not OK, replace the faulty circuit breaker.
2. Remove the power seat switch. Check for battery voltage at the fused B(+) circuit cavity of the switch wire harness connector. If OK, go to
Step 3. If not OK, repair the open circuit to the junction block as required.
3. Check for continuity between the ground circuit cavity of the switch wire harness connector and a good ground. There should be continuity If
OK, go to Step 4. If not OK, repair the open circuit to ground as required.
4. Test the power seat switch as described. If the switch tests OK, check the wire harness for the inoperative motor between the switch and the
motor for shorts or opens. If the circuits check OK, replace the faulty power seat adjuster and motors assembly. If the circuits are not OK,
repair the wire harness as required.
