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Home >> Jeep >> 2004 >> Liberty Limited, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Electronic Control Modules) >> Heated Seat Module >> Diagnosis And Testing - Heated Seat Module >> Left Seat Heater Inoperative

Left Seat Heater Inoperative

WARNING: This page is about a different car, the 2003 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
  1. If a heated seat heats but one or both indicator lamps (LED's) on the heated seat switch fail to illuminate, check the driver circuit with the inoperative LED for a short to ground. If OK, replace the heated seat switch. If NOT OK repair the short to ground as required and than replace the heated seat switch.
    NOTE: IF THE LEFT SEAT CUSHION IS ALREADY WARM, THE FOLLOWING STEP WILL NOT PROVE CONCLUSIVE.
  2. Backprobe the heated seat module wire harness connector, do not disconnect. Check cavity #5 for battery voltage when the left heated seat switch is turned "ON", voltage should be present, If OK go to Step 3 If NOT OK, test the left heated seat switch (Refer to HEATED SEAT SYSTEM ). If the switch tests OK, check for continuity between the switch and control module on the MUX circuit, If OK replace the heated seat control module. If NOT OK, repair the open or shorted MUX circuit as required.
  3. Backprobe the heated seat module wire harness connector, do not disconnect. Check cavity #12 for battery voltage, while observing the voltmeter depress the left heated seat switch low  setting twice, voltage should toggle between about 12V and 8V, If OK go to Step 4. If NOT OK check for continuity between the switch and control module on the low heat driver circuit, If OK replace the heated seat control module.
  4. Backprobe the heated seat module wire harness connector, do not disconnect. Check cavity #14 for battery voltage, while observing the voltmeter depress the left heated seat switch high setting twice, voltage should toggle between about 12V and 8V, If OK go to Step 5. If NOT OK check for continuity between the switch and control module on the high heat driver circuit, If OK replace the heated seat control module.
  5. Backprobe the heated seat module wire harness connector, do not disconnect. Check cavity #2 for about 5V, 5 volts should be present, If OK go to Step 6. If NOT OK replace the heated seat control module.
  6. Backprobe the heated seat module wire harness connector, do not disconnect. Check cavity #8 for a range in voltage from 1.72V (warm seat) - 3.0V (cold seat). It should be within this range, If OK replace the heated seat control module. If NOT OK, test the Heated Seat Sensor. If NOT OK, replace the left heated seat element and sensor assembly. If the heated seat sensor tests OK, check for continuity between the left heated seat cushion connector and control module connector on the 5V supply circuit, If NOT OK, repair the open or shorted 5V supply circuit as required. If OK check for continuity between the left heated seat cushion connector and control module connector on the temperature sensor input circuit. If NOT OK, repair the open or shorted temperature sensor input circuit as required. If OK replace the heated seat control module.
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