Test G: The Defrost System Is Inoperative

PINPOINT TEST G: THE DEFROST SYSTEM IS INOPERATIVE

Normal Operation
Under normal operation, when the rear window defrost switch is depressed on the HVAC module, a request signal is sent to the instrument cluster (IC) through circuit 1010 (DB/OG). Once the IC receives the signal to turn on the rear window defrost, the IC grounds circuit 1009 (OG/YE) to activate the heated rear window relay. Power is then sent to the rear window defrost grid through circuit 186 (BN/LB) from the heated rear window relay. The rear window defrost grid then receives ground through circuit 57 (BK) to chassis ground.

This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Heated rear window relay
- Wiring, terminals or connectors
- HVAC module
- IC

G1-G2:

G2-G4:

G4-G7:

G7-G8: