Both Seat Heater Inoperative

If a heated seat fails to heat and one or both of the indicator lamps on a heated seat switch flash, refer to Heated Seat System Diagnosis and Testing for flashing LED failure identification Testing and Inspection. Refer to Wiring Diagrams in for complete heated seat system wiring diagrams.

Remove the heated seat module from its mounting location (Refer to HEATED SEAT MODULE - REMOVAL Service and Repair).

NOTE: IN ORDER TO PERFORM THE FOLLOWING TESTS IT WILL BE NECESSARY TO REMOVE THE HEATED SEAT RELAY AND INSTALL A JUMPER WIRE IN TERMINALS 87 AND 30, BYPASSING THE HEATED SEAT RELAY.

ANY RESISTANCE VALUES (OHMS ) GIVEN IN THE FOLLOWING TEXT ARE SUPPLIED USING THE AUTOMATIC RANGE GENERATED BY A FLUKE AUTOMOTIVE METER. IF ANOTHER TYPE OF MEASURING DEVICE IS USED THE VALUES GENERATED MAY NOT BE THE SAME AS THE RESULTS SHOWN HERE, OR MAY HAVE TO BE CONVERTED TO THE RANGE USED HERE.

Both Seats Inoperative
If both seats (driver and passenger) fail to heat and the indicator lamps on the heated seat switches for both seats fail to operate, test the heated seat relay and/or fuses. Refer to Relay Diagnosis and Testing Seat Temperature Relay. If the heated seat relay checks OK, go to Step 1.

1. Back-probe the heated seat module wire harness connector, do not disconnect. Check for continuity between the ground circuit cavity # 13 of the heated seat module connector and a good ground.
If OK go to Step 2.
If NOT OK, repair the open or shorted ground circuit as required.

2. Back-probe the heated seat module wire harness connecto, do not disconnect. Check cavity # 4 and # 6 for battery voltage, voltage should be present.
If OK go to Step 3.
If NOT OK repair the open or shorted fused B(+) circuit as required.

3. Back-probe the heated seat module wire harness connector, do not disconnect. Check cavity # 2 for approximately 5 volts, voltage should be present, replace the heated seat control module with a known good module and verify system operation.