Heated Seat Switch Indicator Malfunction

Heated Seat Switch Indicator Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The driver and front passenger heated seats are controlled by separate heated seat switches. The switches are located on the door panels. When a heated seat switch is pressed, ground is momentarily applied through the switch contacts and the switch signal circuit to the door module. In response to this signal, the module then sends a message to the memory seat module via the low speed GMLAN serial data line indicating the heat seat request. The door module then applies voltage through the appropriate indicator control circuits to the heated seat switch illuminating the appropriate indicators.

Circuit/System Verification

1. Ignition ON with the heated seat OFF, the heated seat switch mode indicators should not be illuminated.
2. Ignition ON, use a scan tool to observe the appropriate Door Switch Seat Indicator Cmd. parameter while pressing the heated seat switch. The reading should change between Off and On.

Circuit/System Testing

Heated and Cooled Seat Switch Indicators Inoperative
1. Ignition OFF, disconnect the (C4) harness connector at the door module.
2. Connect a 3A fused jumper wire between the low reference circuit terminal 4 and ground.
3. Connect a test lamp between battery voltage and each indicator control circuit listed below. Each indicator should illuminate when tested.

* Medium heat indicator terminal 1
* High heat indicator terminal 2
* Low heat indicator terminal 9
* Seat back and cushion indicator terminal 10
* Seat back only mode indicator terminal 11

• If any indicator does not illuminate, replace the heated seat switch.

4. If all indicators illuminate, replace the door module.

Heated and Cooled Seat Switch Indicators Always On
1. Ignition OFF, disconnect the (C4) harness connector at the door module.
2. Ignition ON, the heated seat switch mode indicators should not be illuminated.

• If illuminated, test the control circuit of the illuminated indicator for a short to voltage.

3. If all circuits test normal, replace the door module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Front Seat Heater Switch Replacement
* Control Module References for door module replacement, setup, and programming. Programming and Relearning