Test G: The Defrost System Will Not Shut Off Automatically

PINPOINT TEST G: THE DEFROST SYSTEM WILL NOT SHUT OFF AUTOMATICALLY

G1-G3:

G3-G4:

Normal Operation
The heated backlight relay, which is integral to the SJB, receives power from circuit 1846 (GY/LB). When the rear window defrost switch is pressed on the electronic automatic temperature control (EATC) or electronic manual temperature control (EMTC) module, a message is sent to the smart junction box (SJB) through circuit 1426 (PK). Once the SJB receives the message to turn on the rear window defrost, the SJB activates the heated backlight relay. Power is then sent to the rear window defrost grid through circuit 186 (BN/LB) from the SJB heated backlight relay circuit. The rear window defrost grid then receives ground through circuit 1205 (BK) to chassis ground.

Possible Causes
- Inoperative SJB
- Circuit 186 (BN/LB) shorted to power
- Circuit 1427 (TN/LB) shorted to power