For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: The radio vacuum florescent display goes blank and the radio button backlighting goes off when the park lamps are turned on.
1 | Did you perform the Radio/Audio Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Radio/Audio System
2 |

1. Turn the ignition key to the accessory position.
2. Turn the radio on.
3. Turn the park lamps on.
4. Adjust the IP lamp dimmer switch.

Does the radio vacuum florescent display operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 | Test the DC dimming signal circuit for:

• | an open

• | high resistance

• | short to ground

• | or poor connection

Refer to:

• | Circuit Testing

• | Wiring Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Connector Repairs

Did you find and correct the condition?

--

Go to Step 7

Go to Step 4

4 | Test the DC output voltage of the headlamp and IP lamp dimmer switch at the DC dimming signal circuit. Does the voltage vary as the IP dimmer switch is rotated? | -- | Go to Step 5 | Go to Step 6
5 | Replace the radio. Refer to Radio Replacement Did you complete the repair? | -- | Go to Step 7 | --
6 | Replace the headlamp and IP lamp dimmer switch. Refer to Headlamp Switch Replacement Did you complete the repair? | -- | Go to Step 7 | --
7 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2