GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Inspect the left low beam headlamp bulb for a damaged or open filament.
  2. Inspect the left headlamp connector in order to verify that the seal is not missing or damaged.

Is the headlamp bulb and connectors OK?

--

Go to Step 2

Go to Step 9

2

  1. Turn the headlamp switch to the HEAD position.
  2. Turn the headlamp dimmer switch to the LOW position
  3. Using a test light, backprobe between the left headlamp harness connector C141 terminal H and ground.

Does the test light illuminate?

--

Go to Step 5

Go to Step 4

3

Repair a poor connection or an open in circuit 12 between the underhood accessory wiring junction block harness connector C3 terminal A12 and the left headlamp harness connector C141 terminal H.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

4

Using a test light, backprobe between the underhood accessory wiring junction block harness connector C3 terminal A12 and ground.

Does the test light illuminate?

--

Go to Step 3

Go to Step 8

5

Using a test light, backprobe between the left headlamp harness connector C141 terminal H and terminal J.

Does the test light illuminate?

--

Go to Step 7

Go to Step 6

6

Repair a poor connection or an open in circuit 1350 between the left headlamp wiring harness connector C141 terminal J and G101.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

7

Replace the left headlamp. Refer to Headlamp Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

8

Replace the underhood wiring junction block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--

9

Replace the damaged component.

Is the repair complete?

--

Go to Diagnostic System Check - Lighting Systems

--