GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Using a DMM, test circuit 10 for a short to B+.

Is a short to B+ in circuit 10?

--

Go to Step 2

Go to Step 3

2

Repair a short to B+ in circuit 10.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

3

  1. Disconnect the ambient light sensor.
  2. Using a DMM, test for continuity in the ambient light sensor between terminal A to terminal B.

Does continuity exist?

--

Go to Step 4

Go to Step 5

4

Using a DMM, test for continuity in circuit 1137 between the ambient light sensor harness connector terminal B and the automatic headlamp control module harness connector C2 terminal G.

Does continuity exist in circuit 1137?

--

Go to Step 7

Go to Step 6

5

Replace the ambient light sensor. Refer to Ambient Light Sensor Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

6

Repair a poor connection or an open in circuit 1137.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

7

Using a DMM, test for continuity in circuit 1138 between the ambient light sensor harness connector terminal A and the automatic headlamp control module connector C2 terminal H.

Does continuity exist in the circuit?

--

Go to Step 9

Go to Step 8

8

Repair a poor connection or an open in circuit 1138.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

9

Replace the automatic headlamp control module.

Refer to Headlamp Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--