Heated Seat Inoperative

Heated Seat Inoperative

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.

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 door module sends a message via the low speed GMLAN serial data line to the memory seat module (MSM) 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, observe the following scan tool parameters in the appropriate driver or passenger door switch data list while pressing and releasing the appropriate switch. The readings should change between ACTIVE and INACTIVE.

* Seat Back Heat Mode Sw.
* Seat Heat Mode Sw.

^ If not the specified value, refer to Heated Seat Switch Malfunction.

2. If the switches operate normally, replace the appropriate door control module.

Circuit/System Testing

Heated Seat Switch Malfunction
1. Ignition OFF, disconnect the X4 harness connector at the appropriate door module.
2. Test for infinite resistance between the following switch signal circuits and ground with the switch in the open position.

* Terminal 6 heated seat back cushion heat switch signal
* Terminal 7 heated seat back only mode switch signal

^ If less than the specified range for either of the tests, replace the heated seat switch.

3. Test for less than 2 ohms between the following switch signal circuits and ground with the switch in the closed position.

* Terminal 6 heated seat back cushion heat switch signal
* Terminal 7 heated seat back only mode switch signal

^ If greater than the specified range, test the heated seat switch ground circuit for an open/high resistance. If the circuit test normal, test or replace the heated seat switch.

Repair Instructions

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

* Heated Seat Switch Replacement