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 Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 in Wiring Systems

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 in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

--

6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2