Heated Seat Inoperative (Dealer Installed, KA1)
Heated Seat Inoperative (Dealer Installed, KA1)
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 heated seat module (HSM). In response to this signal, the module then applies battery voltage through the element supply voltage circuits to the seat cushion and seat back heating elements. The HSM then supplies a ground through the appropriate indicator control circuits to the heated seat switch illuminating the switch 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 Heated Seat Module parameter listed below while pressing and releasing the heated seat back and cushion switch. The readings should change between Off and Back & Cushion.
* Driver Seat HVC Mode
* Passenger Seat HVC Mode
• If not the specified value, refer to Heated Seat Switch Malfunction.
2. Ignition ON, observe the appropriate scan tool Heated Seat Module parameter listed below while pressing and releasing the heated seat back only switch. The readings should change between Off and Back Only.
* Driver Seat HVC Mode
* Passenger Seat HVC Mode
• If not the specified value, refer to Heated Seat Switch Malfunction.
3. If all heated seat switch functions operate OK, but, one or more of the heated seat switch indicators is inoperative or always ON, refer to Heated Seat Switch Indicator Malfunction.
4. If all scan tool parameters test normal and there are no DTCs set, replace the HSM.
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 appropriate scan tool Heated Seat Module parameter listed below is Off.
* Driver Seat HVC Mode
* Passenger Seat HVC Mode
• If not the specified value, test the signal circuits listed below for a short to ground. If the circuits test normal, replace the HSM.
* Seat cushion and back signal terminal 4
* Seat back only signal terminal 5
4. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the appropriate scan tool Heated Seat Module parameter listed below is Back & Cushion.
* Driver Seat HVC Mode
* Passenger Seat HVC Mode
• If not the specified value, test the signal circuit for a short to voltage an open/high resistance. If the circuit tests normal, replace the HSM.
5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the appropriate scan tool Heated Seat Module parameter listed below is Back Only.
* Driver Seat HVC Mode
* Passenger Seat HVC Mode
• 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 HSM.
6. 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, verify that a test lamp illuminates between the control circuit terminal 2 and ground. If the test lamp does not illuminate, refer to Interior Backlighting Malfunction Interior Backlighting Malfunction.
3. Ignition OFF, connect the harness connector at the heated seat switch.
4. Disconnect the X3, X4 harness connectors at the heated seat module.
5. Ignition ON, connect a test lamp between the control circuits listed below and ground. The appropriate indicator should turn ON and OFF when the test lamp is connected and disconnected.
* Driver seat high heat indicator terminal 5 X3
* Driver seat medium heat indicator terminal 16 X4
* Driver seat low heat indicator terminal 4 X3
* Driver seat back and cushion heat indicator terminal 17 X4
* Driver seat back heat indicator terminal 15 X4
* Passenger seat high heat indicator terminal 10 X3
* Passenger seat medium heat indicator terminal 6 X4
* Passenger seat low heat indicator terminal 9 X3
* Passenger seat back and cushion heat indicator terminal 7 X4
* Passenger seat back heat indicator terminal 18 X4
• If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, test or replace the heated seat switch.
• If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the heated seat switch.
6. If all circuits test normal, replace the HSM.
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 5 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 5 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 control terminal 2 and B+.
7. Connect a test lamp between the control circuits listed below and ground. The selected indicator should illuminate.
* 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 any indicator does not illuminate, replace the heated seat switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Programming and Relearning for heated seat control module replacement, setup, and programming