GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Headlights/Daytime Running Lights (DRL) Circuit Description and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Turn the ignition switch to ON .
  2. Cover the ambient light sensor while observing the headlamps.

Did the headlamps illuminate at full intensity?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Did the exterior lights illuminate?

Go to Step 6

Go to Step 4

4

  1. Disconnect the ambient light sensor connector.
  2. Test the ignition positive voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find correct the condition?

Go to Step 9

Go to Step 5

5

Test the ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find correct the condition?

Go to Step 9

Go to Step 8

6

  1. Disconnect the ambient light sensor connector.
  2. Connect a 3 amp fused jumper from cavity 4 to cavity 6 of the connector.

Did the headlamps illuminate?

Go to Step 8

Go to Step 7

7

Test the headlamp relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

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8

Replace the ambient light sensor. Refer to Daytime Running Lamp (DRL) Ambient Light Sensor Replacement .

Did you complete the repair?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3