Rear Heated Seat Malfunction (With CJ4)
Rear Heated Seat Malfunction (With CJ4)
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 rear seat heated seat switches are located in the auxiliary HVAC control module. When a heated seat switch is pressed, a serial data message is sent to the HVAC control module indicating the heated seat request. The HVAC control module serves as a gateway to transmit the message to the rear seat heating control module via the serial data line. In response to this message, the rear seat heating control module applies battery voltage through the heater element control circuits to the appropriate seat heating elements.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Rear Heated Seats Description and Operation Rear 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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Body Control Module Left Rear Seat Heating Switch parameter changes between Inactive and Active when pressing the left rear heated seat switch.
• If the parameter does not change
Replace the K33A HVAC Control Module - Auxiliary
• If the parameter changes
3. Verify the scan tool Right Rear Heated Seat Switch parameter changes between Inactive and Active when pressing the heated seat switch.
• If the parameter does not change
Replace the K33A HVAC Control Module - Auxiliary
• If the parameter changes
4. Refer to Circuit/System Testing.
Circuit/System Testing
Note: Circuit/System Verification must be performed before proceeding with Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the X2 harness connector at the K29R Rear Seat Heating Control Module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 7 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminals listed below and ground.
* Terminal 2
* Terminal 3
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K29R Rear Seat Heating Control Module.
5. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate E14 Seat Heating Element. It may take up to 2 minutes for all vehicle systems to power down.
6. Test for less than 10 ohms between the ground circuit terminal A and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
7. Ignition ON, connect a test lamp between the control circuit terminal B and the ground circuit terminal A.
8. Verify the test lamp turns ON and OFF when commanding the appropriate Driver or Passenger Seat Heating element ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X2 harness connector at the K29R Rear Seat Heating Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K29R Rear Seat Heating Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the X2 harness connector at the K29R Rear Seat Heating Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K29R Rear Seat Heating Control Module.
• If the test lamp turns ON and OFF
9. Test or replace the E14 Seat Heating Element.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Rear Seat Back Cushion Heater Replacement (40%) Rear Seat Back Cushion Heater Replacement (40%)Rear Seat Back Cushion Heater Replacement (60%) Rear Seat Back Cushion Heater Replacement (60%)
* Rear Seat Cushion Heater Replacement Rear Seat Cushion Heater Replacement
* Control Module References Control Module References for the K33A HVAC Control Module - Auxiliary and the K29R Rear Seat Heating Control Module replacement, programming and setup