Pinpoint Test D: The Audio Unit Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Test

Pinpoint Test D: The Audio Unit Illumination Is Inoperative

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

Normal Operation

The instrument panel dimmer switch provides variable voltage to the audio unit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Audio unit



PINPOINT TEST D: THE AUDIO UNIT ILLUMINATION IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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D1 CHECK THE AUDIO UNIT INPUT CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: Audio Unit C290a.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the audio unit C290a-1, circuit VLN18 (BU/WH), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to D2.

No
REPAIR circuit VLN18 (BU/WH) for an open. TEST the system for normal operation.

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D2 CHECK THE AUDIO UNIT GROUND CIRCUIT FOR AN OPEN


- Place the headlamp switch in the OFF position.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the audio unit C290a-2, circuit GD161 (BK/YE), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
SEND the audio unit to an authorized audio system repair facility. REFER to Accessories and Optional Equipment. TEST the system for normal operation.

No
REPAIR circuit GD161 (BK/YE) for an open. TEST the system for normal operation.

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