Schematic Reference: Interior Lights Dimming Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Are all of the interior backlighting lamps always ON?

Go to Step 3

Go to Step 8

1. Install the scan tool.
2. With a scan tool, observe the Dimming Pot A/D parameter in the IPM inputs data list.
3. Turn the instrument panel (I/P) dimmer switch from minimum to maximum intensity.

Does the scan tool indicate that the Dimming Pot A/D parameter is changing when the I/P dimmer switch is moved?

Go to Step 4

Go to Step 6

With a scan tool, observe the Park Lamp Switch status in the IPM inputs data list.

Does the scan tool display ON?

Go to Step 5

Go to Step 7

With a scan tool, observe the Ambient Light Status parameter in the lighting data list.

Does the scan tool display DARK?

Go to Step 10

Go to Twilight Sentinel Inoperative

Test the I/P dimmer switch low reference circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 9

Test the park lamp relay control circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 10

Inspect for poor connections at the harness connector of the appropriate control module of the inoperative backlight lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 11

Inspect for poor connections at the harness connector of the I/P dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 12

Inspect for poor connections at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 13

Replace the appropriate control module for the inoperative backlight lamp. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

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Replace the I/P lamps dimmer switch. Refer to Instrument Panel Lamp Dimmer Switch Replacement .

Did you complete the replacement?

Go to Step 14

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Replace the IPM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2