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Heated Seat Inoperative




Heated Seat Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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 door module then 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.

Reference Information
Schematic Reference

Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Heated Seats Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for Scan Tool Information

Circuit/System Verification

Ignition ON, observe the scan tool Driver Door Switch and Passenger Door Switch parameters listed below while pressing and releasing the appropriate switch. The readings should change between Active and Inactive.

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

Circuit/System Testing

Driver Heated Seat Inoperative
1. Ignition OFF, disconnect the harness connector at the driver heated seat switch.
2. Ignition OFF, test for less than 10 Ohms between the low reference circuit terminal 3 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the door module.

3. Ignition ON, verify the scan tool Seat Heat Mode Sw. parameter is Inactive.

• If not the specified value, test the signal circuit terminal 8 for a short to ground. If the circuit tests normal, replace the door control module.

4. Install a 3 A fused jumper wire between the signal circuit terminal 8 and ground. Verify the scan tool Seat Heat Mode Sw parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door control module.

5. Ignition ON, verify the scan tool Seat Back Heat Mode Sw. parameter is Inactive.

• If not the specified value, test the signal circuit terminal 11 for a short to ground. If the circuit tests normal, replace the door control module.

6. Install a 3 A fused jumper wire between the signal circuit terminal 11 and ground. Verify the scan tool Seat Back Heat Mode Sw parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door control module.

7. If all circuits test normal, test or replace the heated seat switch.

Passenger Heated Seat Inoperative
1. Ignition OFF, disconnect the harness connector at the passenger heated seat switch.
2. Ignition OFF, test for less than 10 Ohms between the low reference circuit terminal 5 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the door module.

3. Ignition ON, verify the scan tool Seat Heat Mode Sw. parameter is Inactive.

• If not the specified value, test the signal circuit terminal 14 for a short to ground. If the circuit tests normal, replace the door control module.

4. Install a 3 A fused jumper wire between the signal circuit terminal 14 and ground. Verify the scan tool Seat Heat Mode Sw parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door control module.

5. Ignition ON, verify the scan tool Seat Back Heat Mode Sw. parameter is Inactive.

• If not Inactive, test the signal circuit terminal 11 for a short to ground. If the circuit tests normal, replace the door control module.

6. Install a 3 A fused jumper wire between the signal circuit terminal 11 and ground. Verify the scan tool Seat Back Heat Mode Sw parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door control module.

7. If all circuits test normal, test or replace the heated seat switch.

Component Testing

Driver Heated Seat Switch
1. Ignition OFF, disconnect the harness connector at the heated seat switch.
2. Test for infinite resistance between the following switch signal circuits and the low reference circuit terminal 3 with the switch in the open position.

* Terminal 8 heated seat back cushion heat switch signal
* Terminal 11 heated seat back only mode switch signal

• If not the specified value, replace the heated seat switch.

3. Test for less than 2 Ohms between the signal circuit terminals listed below and the low reference circuit terminal 3 with the switch in the closed position.

* Terminal 8 heated seat back cushion heat switch signal
* Terminal 11 heated seat back only mode switch signal

• If greater than the specified value, replace the heated seat switch.

Passenger Heated Seat Switch
1. Ignition OFF, disconnect the harness connector at the heated seat switch.
2. Test for infinite resistance between the signal circuit terminals listed below and the low reference circuit terminal 5 with the switch in the open position.

* Terminal 14 heated seat back cushion heat switch signal
* Terminal 11 heated seat back only mode switch signal

• If not the specified value, replace the heated seat switch.

3. Test for less than 2 Ohms between the signal circuit terminals listed below and the low reference circuit terminal 5 with the switch in the closed position.

* Terminal 14 heated seat back cushion heat switch signal
* Terminal 11 heated seat back only mode switch signal

• If greater than the specified range, replace the heated seat switch.

Repair Instructions

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

* Driver Seat Heater Switch Replacement (Driver Seat Heater Switch Replacement)
* Passenger Seat Heater Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for door module replacement, setup, and programming

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