GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Is the problem with the low beams?

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Go to Step 2

Go to Step 7

2

  1. Disconnect the inoperative headlamp.
  2. Turn the headlamp switch to the HEAD position.
  3. Turn the headlamp dimmer switch to the LOW position.
  4. Using a test light, probe between the headlamp harness connector terminal A to ground.

Does the test light illuminate?

--

Go to Step 3

Go to Step 4

3

Replace the headlamp. Refer to Headlamp Replacement .

Is the repair complete?

--

Go to Daytime Running Lights (DRL) System Check

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4

Disconnect the underhood accessory wiring junction block connector C3.

    • For the left side: using a test light, probe between B+ to the underhood accessory wiring junction block connector C3 terminal B8.
    • For the right side: using a test light, probe between B+ to the underhood accessory wiring junction block connector C3 terminal A8.

Does the test light illuminate?

--

Go to Step 5

Go to Step 6

5

Replace the underhood accessory wiring junction block. Refer to Junction Block Replacement - Accessory Wiring in Body Front End.

Is the repair complete?

--

Go to Daytime Running Lights (DRL) System Check

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6

    • For the left side: repair the poor connection or open in CKT 12 between the underhood accessory wiring junction block harness connector C3 terminal A8 and the headlamp connector terminal A.
    • For the right side: repair the poor connection or open in CKT 12 between the underhood accessory wiring junction block harness connector C3 terminal A8 and the headlamp connector terminal A.

Is the repair complete?

--

Go to Daytime Running Lights (DRL) System Check

--

7

  1. Disconnect the inoperative headlamp.
  2. Turn the headlamp switch to the HEAD position.
  3. Turn the headlamp dimmer switch to the HIGH position.
  4. Using a test light, probe between the headlamp connector terminal C to ground.

Does the test light illuminate?

--

Go to Step 3

Go to Step 8

8

Disconnect the underhood accessory wiring junction block connector C3.

    • For the left side: using a test light, probe between B+ and the underhood accessory wiring junction block connector C3 terminal B4.
    • For the right side: using a test light, probe between B+ and the underhood accessory wiring junction block connector C3 terminal A4.

Does the test light illuminate?

--

Go to Step 5

Go to Step 9

9

    • For the left side: repair the poor connection or open in CKT 11 between the underhood accessory wiring junction block harness connector C3 terminal B4 and the headlamp connector terminal C.
    • For the right side: repair the poor connection or open in CKT 11 between the underhood accessory wiring junction block harness connector C3 terminal A4 and the headlamp connector terminal C.

Is the repair complete?

--

Go to Daytime Running Lights (DRL) System Check

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