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: Master Electrical Component List

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. Turn OFF the wipers.
  3. Position the headlamps switch in the AUTO position.
  4. Position the headlamp dimmer switch to the low beam position.
  5. Depress and hold the brake pedal.
  6. Move the gear selector out of park position.
  7. Verify the parking brake is disengaged.
  8. Expose the sunload sensor assembly to a bright light.
  9. Observe the headlamps.
  10. Wait about 20 seconds.
  11. Cover the sunload sensor assembly.
  12. Wait about 20 seconds.
  13. Place the gear selector in the park position.
  14. Release the brake pedal.
  15. Turn OFF the ignition.

Do the headlamps switch between low beam and daytime running lamps (DRL)?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the DRL and headlamps operate properly?

Go to Step 4

Go to Daytime Running Lamps (DRL) Inoperative or Headlamps Inoperative - Low Beams

4

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Position the headlamps switch in the AUTO position.
  4. With a scan tool, observe the twilight switch parameter in the dash integration module (DIM) Inputs data list.

Does the twilight switch parameter display ON?

Go to Step 9

Go to Step 5

5

  1. Disconnect the multifunction, turn signal switch.
  2. Connect a 3-amp fused jumper between the twilight sentinel delay signal circuit of the multifunction, turn signal switch and the ground circuit of the multifunction, turn signal switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the twilight switch position parameter in the dash integration module (DIM) Inputs data list.

Does the twilight switch parameter display ON?

Go to Step 8

Go to Step 6

6

Test the ground circuit of the multifunction, turn signal switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 7

7

Test the twilight sentinel delay signal circuit of the multifunction, turn signal switch for a high resistance, an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the multifunction, turn signal switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 10

9

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

Did you find and correct the condition?

Go to Step 12

Go to Step 11

10

Replace the multifunction, turn signal switch. Refer to Turn Signal Multifunction Switch Replacement .

Did you complete the replacement?

Go to Step 12

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11

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

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2