Test B: The Heated Seat Is Inoperative/Does Not Operate Correctly - Driver

PINPOINT TEST B: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - DRIVER

Normal Operation
The driver seat has a heated seat relay mounted to the seat track. There are 2 voltage supplies to the heated seat relay. When the ignition switch is ON, voltage is supplied from the smart junction box (SJB) to the heated seat relay coil through heated seat relay enable circuit CHS25 (YE). When the engine is running and the heated seat switch is pressed on, ground is supplied to the opposite side of the relay coil by HVAC module driver heated seat relay drive circuit CHS29 (WH/BU) to energize the relay. The switch indicator can only be illuminated with the engine running. The relay contact closes to supply battery voltage from circuit CHS02 (YE/BU) to the driver heater mat circuit CHS11 (VT/GN). The driver heater mats are connected to ground circuit GD906 (BK/GY) completing the electrical circuit to heat the seat.

- DTC B12AB Drivers Heated Seat Relay Drive Circuit Shorted to Battery Voltage - If the driver heated seat relay drive circuit CHS02 (YE/BU) is shorted to voltage and the HVAC module attempts to activate the driver heated seat relay, the DTC will set and the seat will fail to heat.
- DTC B12AC Drivers Heated Seat Relay Drive Circuit Open or Shorted to Ground - If the driver heated seat relay drive circuit CHS02 (YE/BU) is open or shorted to ground and the HVAC module attempts to activate the driver heated seat relay, the DTC will set and the seat will fail to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition key is OFF.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat relay
- Backrest or cushion heater mat
- HVAC module

B1-B4:

B4-B5:

B6-B8:

B8-B9:

B10-B12:

B12-B13: