GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Expose the sunload sensor to a bright light.
  3. Place the wiper/washer switch in the OFF position.
  4. Place the headlamp switch in the OFF position.
  5. Place the fog lamp switch in the OFF position.
  6. Wait more than 6 seconds.

Does the HEADLAMPS SUGGESTED message display on the instrument panel cluster (IPC)?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Install a scan tool.
  2. Observe the Photocell Status in the Climate Control Panel (CCP) Inputs data list.

Does the scan tool display Light?

Go to Step 4

Go to Twilight Sentinel Inoperative

4

Inspect for poor connections at the harness connector of the dash integration module (DIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

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

Did you complete the replacement?

Go to Step 6

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6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2