Test E: The Defrost System Is Inoperative
PINPOINT TEST E: THE DEFROST SYSTEM IS INOPERATIVENormal Operation
The heated rear window is controlled by the driver's door module (DDM). The ignition switch must be in RUN for the DDM to operate. When the rear window defrost switch is pressed, the DDM provides a ground for the rear window defrost relay coil through circuit 688 (GY/LB). The rear window defrost relay coil is energized, providing battery voltage to the antenna module on circuit 186 (BN/LB). The antenna module then supplies voltage and ground to the heated rear window grid.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Rear window defrost relay
- Rear window defrost switch
- Heated rear window grid
- Antenna module
- DDM