GM Service Manual Online
For 1990-2009 cars only

Headlamps Do Not Switch Intensity Domestic

Step

Action

Value(s)

Yes

No

1

Was the entire DRL system check performed?

--

Go to Step 2

Go to Daytime Running Lights (DRL) System Check

2

Is the DRL always in the daylight mode (the low beam headlights on at a reduced intensity)?

--

Go to Step 3

Go to Step 4

3

Disconnect the DRL ambient light sensor.

Does the DRL change modes?

--

Go to Step 5

Go to Step 6

4

  1. Disconnect the DRL ambient light sensor.
  2. Attach a 3A fused jumper between the ambient light sensor harness connector terminal A and terminal B.

Does the DRL change modes?

--

Go to Step 5

Go to Step 9

5

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

Is the repair complete?

--

Go to Step 13

--

6

Inspect for a short to ground in CKT 1137.

Is there a short to ground in CKT 1137?

--

Go to Step 7

Go to Step 8

7

Repair a short to ground in CKT 1137.

Is the repair complete?

--

Go to Step 13

--

8

Replace the DRL module. Refer to Daytime Running Lights (DRL) Control Module Replacement

Is the repair complete?

--

Go to Step 13

--

9

Inspect for the following conditions in CKT 1138:

    • A poor connection
    • An open

Is there a poor connection or an open in CKT 1138?

--

Go to Step 10

Go to Step 11

10

Repair a poor connection or open in circuit 1138.

Is the repair complete?

--

Go to Step 13

--

11

Inspect for the following conditions in CKT 1137:

    • A poor connection
    • An open

Is there a poor connection or an open in CKT 1137?

--

Go to Step 12

Go to Step 8

12

Repair a poor connection or open in circuit 1137.

Is the repair complete?

--

Go to Step 13

--

13

  1. Turn the ignition switch to the OFF position.
  2. Reconnect all connectors/components removed.

Have all repairs been made?

--

Go to Daytime Running Lights (DRL) System Check

--