• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Heated Seat Relay B+ | 1, B1920, B2165 | 1, B1920, B2165 | -- | -- |
Heated Seat Relay Control | 1, B2508, B2509 | B2508, B2509 | B2508, B2509 | -- |
Heated Seat Relay Ground | -- | B2508, B2509 | -- | -- |
Heated Seat Cushion Temperature Sensor Signal | B1925, B2170 | B1920, B2165 | B1920, B1925, B2165, B2170 | -- |
Heated Seat Cushion Temperature Sensor Low Reference | -- | 1, B1920, B2165 | -- | -- |
Heated Seat Heater Element Control | 1, B1920, B2165 | 1, B1920, B2165 | -- | -- |
Heated Seat Element Ground | -- | 1, B1920, B2165 | -- | -- |
1. Front heated seat malfunction |
The driver and passenger heated seats are controlled by separate heated seat switches. Both switches are located in the HVAC control module. When a heated seat switch is pressed, the HVAC control module sends a class 2 serial data message to the body control module (BCM) indicating the heated seat command. In response to this signal, the BCM applies battery positive voltage through the heated seat relay control circuit energizing the relay coil. The relay closes its switch contacts applying battery positive voltage through the element supply voltage circuit to the seat heating elements. The BCM then sends a class 2 serial data message back to the HVAC control module to illuminate the appropriate temperature indicator.
Heated Seats Description and Operation
Control Module References for scan tool information
⇒ | If the reading does not change between the specified values and no current or history DTCs are set, replace the HVAC control module. |
⇒ | If the reading does not change between the specified values and no current or history DTCs are set, replace the HVAC control module. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal C1 for a short to ground. |
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If not within the specified range, replace the seat back heater element. |
⇒ | If not within the specified range, replace the seat cushion heater element. |
⇒ | If the seat does not get warm, test the control circuit and the circuit between the seat heater elements for a short to ground or an open/high resistance. |
⇒ | If not within the specified range, replace the seat cushion heater element. |
⇒ | If not within the specified range, replace the seat cushion heater element. |
⇒ | If not within the specified range, replace the seat back heater element. |
⇒ | If the resistance is not within the specified range, replace the relay. |
• | 30 and 85 |
• | 30 and 86 |
• | 30 and 87 |
• | 85 and 87 |
⇒ | If not the specified value, replace the heated seat relay. |
⇒ | If greater than the specified range, replace the heated seat relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM and HVAC control module replacement, setup, and programming |