Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ MSM Terminal 5 X3 | 1, 3, B1935 0C, B1935 0D, B2180 0C, B2180 0D, B2425 0C, B2425 0D, B2430 0C, B2430 0D | 1, 3, B1935 0C, B1935 0D, B2180 0C, B2180 0D, B2425 0C, B2425 0D, B2430 0C, B2430 0D | -- | -- |
Heated Seat Back/Cushion Switch Signal | 1 | 1 | 1 | -- |
Heated Seat Back Only Mode Switch Signal | 1 | 1 | 1 | -- |
Heated Seat Back Only Mode Indicator Control | 2 | 2 | 2 | -- |
Heated Seat Back/Cushion Indicator Control | 2 | 2 | 2 | -- |
Heated Seat Cool Indicator Control | 2 | 2 | 2 | -- |
Heated Seat High Temperature Indicator Control | 2 | 2 | 2 | -- |
Heated Seat Low Temperature Indicator Control | 2 | 2 | 2 | -- |
Heated Seat Medium Temperature Indicator Control | 2 | 2 | 2 | -- |
Heated Seat Switch Low Reference | 1 | 1 | -- | -- |
1. Heated seat inoperative 2. Heated seat switch indicator malfunction 3. Power seats inoperative | ||||
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 serial data message 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
Connector End View Reference
Description and Operation
Heated Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
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 Back Heat Mode Sw. |
| • | Seat Heat Mode Sw. |
| ⇒ | If not the specified value, perform the Heated Seat Switch component test. If the switch tests normal, replace the appropriate door control module. |
Circuit/System Testing
- Ignition OFF, disconnect the X3 harness connector at the MSM.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
- If all circuits test normal and there are no DTCs set, replace the MSM.
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
Component Testing
Heated Seat Switch
- Ignition OFF, disconnect the X4 harness connector at the appropriate door module.
- Test for infinite resistance between the signal terminals listed below and the low reference circuit terminal 4 with the switch in the open position.
- Test for less than 2 ohms between the signal terminals listed below and the low reference circuit terminal 4 with the switch in the closed position.
| • | Heated seat back cushion heat switch signal terminal 6 |
| • | Heated seat back only mode switch signal terminal 7 |
| ⇒ | If not the specified value, replace the heated seat switch. |
| • | Heated seat back cushion heat switch signal terminal 6 |
| • | Heated seat back only mode switch signal terminal 7 |
| ⇒ | If greater than the specified range, replace the heated seat switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for DDM, PDM, or MSM replacement, setup, and programming |
