Test K: The Defrost System Is Inoperative
PINPOINT TEST K: THE DEFROST SYSTEM IS INOPERATIVEK1-K3:
K3-K6:
K6-K7:
K7-K8:
K9-K11:
K11-K13:
K13-K14:
Normal Operation
During normal operation, the ICM receives a ground input through circuit 1010 (DB/OG) from the function selector switch assembly (or EATC module if equipped) when the defrost is desired. The ICM activates the rear window defrost relay by grounding the relay coil through circuit 1009 (OG/YE). When the defrost relay is activated, power is supplied from the relay to the rear window defrost grid through circuit 186 (BN/LB) and also to the function selector switch assembly (or EATC module if equipped) and LH/RH exterior rear view mirror heaters through circuit 59 (DG/VT). Ground is supplied to the rear window defrost grid and exterior mirror heaters through circuit 57 (BK).
Possible Causes
- Fuse(s)
- Rear window defrost relay
- Open in circuit 59 (DG/VT), 1010 (DB/OG), 875 (BK/LB), 1009 (OG/YE), 57 (BK) or 186 (BR/LB)
- Mode switch or EATC module (if equipped with automatic climate control)
- Instrument cluster module (ICM)
- Open or short in rear window defrost grid