GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Diagnostic System Check?

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Go to Step 2

Diagnostic System Check - Lighting Systems

2

Check for continuity in the following CKT's:

    • CKT 634 (YEL) between splice S254 and cavity A of the DRL diode.
    • CKT 815 (WHT) between cavity B of the DRL diode and cavity 9 of relay center #2 (DRL relay).

Was a faulty wire found?

--

Go to Step 3

Go to Step 4

3

Locate and repair OPEN in faulty CKT.

Is the repair complete?

--

Go to Step 7

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4

Check for continuity in the following CKT's:

    • CKT 39 (PNK) between splice S213 and cavity 6 of the DRL relay.
    • CKT 592 (LT GRN/BLK) between cavity 10 of the DRL relay and cavity A11, C1 of the BCM.

Was a faulty wire found?

--

Go to Step 3

Go to Step 5

5

Install a known good DRL relay.

Do the DRL lamps operate?

--

Go to Step 7

Go to Step 6

6

Replace the DRL diode.

Is the repair complete?

--

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2