With Memory A45
Heated Seat Inoperative (With Memory A45)
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. When a heated seat switch is pressed, ground is momentarily applied through the switch contacts and the switch signal circuit to the door lock/window switch. In response to this signal, the door lock/window switch sends serial data a message to the memory seat module (MSM) indicating the heat seat request. The door lock/window switch then applies voltage through the appropriate indicator control circuits to the heated seat switch illuminating the indicators.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (Except A45) Heated/Cooled Seat SchematicsHeated/Cooled Seat Schematics (With KA1) Heated/Cooled Seat Schematics (With KA1)Heated/Cooled Seat Schematics (With KB6) Heated/Cooled Seat Schematics (With KB6)
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
Heated Seats Description and Operation Heated Seats
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
1. Ignition ON, observe the appropriate scan tool Driver or Passenger Door Switch parameters listed below while pressing and releasing the appropriate heated seat switch. The readings should change between Inactive and Active.
* Seat Heat Mode Sw.
* Seat Back Heat Mode Sw.
• If not the specified value, refer to Circuit/System Testing.
2. If all heated seat switch functions operate OK, but, one or more of the heated seat switch indicators is inoperative or is always ON, refer to Heated Seat Switch Indicator Malfunction.
3. If all scan tool parameters test normal and there are no DTCs set, replace the MSM.
Circuit/System Testing
Heated Seat Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
2. Test for less than 10 ohms between the ground circuit terminal 7 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Seat Heat Mode Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the appropriate driver or passenger door lock/window switch.
4. Verify the scan tool Seat Back Heat Mode Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the appropriate driver or passenger door lock/window switch.
5. Install a 3 A fused jumper wire between the signal circuit terminal 4 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 appropriate driver or passenger door lock/window switch.
6. Install a 3 A fused jumper wire between the signal circuit terminal 5 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 appropriate driver or passenger door lock/window switch.
7. If all circuits test normal, test or replace the heated seat switch.
Heated Seat Switch Indicator Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
2. Ignition ON, connect a test lamp between the control circuits listed below and ground. Command the Heated Seat Indicator ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
* Back and cushion heat indicator terminal 1
* Low heat indicator terminal 6
* Medium heat indicator terminal 8
* Back only heat indicator terminal 9
* High heat indicator terminal 10
• If the test lamp is always ON, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the door lock/window switch.
• If the test lamp is always OFF, test the appropriate control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the door lock/window switch.
3. If all circuits test normal, test or replace the heated seat switch.
Component Testing
Heated Seat Switch
1. Ignition OFF, disconnect the harness connector at the heated seat switch switch.
2. Test for infinite resistance between the signal terminal 4 and the ground terminal 7 with the back and cushion switch in the open position.
• If not the specified value, replace the heated seat switch switch.
3. Test for infinite resistance between the signal terminal 5 and the ground terminal 7 with the back only switch in the open position.
• If not the specified value, replace the heated seat switch switch.
4. Test for less than 2 ohms between the signal terminal 4 and the ground terminal 7 with the back and cushion switch in the closed position.
• If greater than the specified value, replace the heated seat switch.
5. Test for less than 2 ohms between the signal terminal 5 and the ground terminal 7 with the back only switch in the closed position.
• If greater than the specified value, replace the heated seat switch.
6. Install a 3 A fused jumper wire between the ground terminal 7 and ground.
7. Connect a test lamp between the control circuits listed below and B+. The selected switch indicator should illuminate.
* Back and cushion heat indicator terminal 1
* Low heat indicator terminal 6
* Medium heat indicator terminal 8
* Back heat indicator terminal 9
* High heat indicator terminal 10
• If any indicator does not illuminate, 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 memory seat module and driver or passenger door lock/window switch replacement, programming, and setup