Test G: The Defrost System Will Not Shut Off Automatically
PINPOINT TEST G: THE DEFROST SYSTEM WILL NOT SHUT OFF AUTOMATICALLYG1-G2:
G3-G5:
G6:
Normal Operation
Under normal operation the heated backlight power relay receives power from circuit 185 (BK) and 326 (WH/VT). When the rear window defrost switch is depressed on the dual automatic temperature control (DATC) control unit, a ground signal is sent to the instrument cluster module (ICM) through circuit 688 (GY/LB). When the ICM receives ground through circuit 688 (GY/LB), the ICM grounds circuit 1009 (OG/YE) to activate the heated backlight power relay. Power is then sent to the rear window defrost grid through circuit 186 (BN/LB) from the heated backlight power relay. The rear window defrost grid then receives ground through circuit 1205 (BK) to chassis ground.
Possible Causes
- Inoperative ICM
- Inoperative heated backlight power relay
- Open in circuit 186 (BN/LB)
- Short to ground in circuit 1009 (OG/YE) or circuit 688 (GY/LB)