Pinpoint Test H: The Rear Window Defrost Switch Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Tests

Pinpoint Test H: The Rear Window Defrost Switch Illumination Is Inoperative

Refer to Wiring Diagram Set 71, Cluster and Panel Illumination for schematic and connector information. Diagrams By Number

Normal Operation

A variable Pulse Width Modulated (PWM) voltage is supplied to the rear window defrost switch illumination from the instrument panel dimmer switch (part of the headlamp switch) when the side, main or parking lamps are on.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Rear window defrost switch


PINPOINT TEST H: THE REAR WINDOW DEFROST SWITCH ILLUMINATION IS INOPERATIVE

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H1 CHECK THE REAR WINDOW DEFROST SWITCH ILLUMINATION CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: Rear Window Defrost Switch C241.
- With the parking lamps on, rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the rear window defrost switch C241-5, circuit 29S-HB31 (OG), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
INSTALL a new rear window defrost switch. TEST the system for normal operation.

No
REPAIR circuit 29S-HB31 (OG) for an open. TEST the system for normal operation.

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