GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the marker lamps are inoperative.

Do the marker lamps operate normally?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Turn the Multifunction Switch (Headlamp Switch) to the HEAD position.

Are all of the Side Marker lamps inoperative?

--

Go to Step 4

Go to Step 9

4

Test the following circuits for an open, high resistance or short to ground. Refer to Circuit Testing in wiring systems.

    • CKT 240 (ORN)
    • CKT 256 (PPL)
    • CKT 74 (LT BLU)
    • CKT 850 (BLK)

Was a problem found?

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Go to Step 5

Go to Step 6

5

Locate and repair the following circuits for an open, high resistance or short to ground. Refer to Wiring Repairs in wiring systems.

    • CKT 240 (ORN)
    • CKT 256 (PPL)
    • CKT 74 (LT BLU)
    • CKT 850 (BLK)

Is the repair complete?

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Go to Step 16

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6

Using a J 39200 Digital Multimeter (DMM), disconnect and test the Multifunction Switch (Headlamp Switch) for continuity between connector C 1 cavity A and cavity C in the PARK and HEAD positions. Refer to Circuit Testing in wiring systems.

Is continuity present?

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Go to Step 8

Go to Step 7

7

Replace the Multifunction Switch (Headlamp Switch). Refer to Turn Signal Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Is the repair complete?

--

Go to Step 16

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8

Replace the Park Lamp Switch Relay.

Is the repair complete?

--

Go to Step 16

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9

Remove the inoperative lamp and inspect the filament.

Is the lamp open?

--

Go to Step 10

Go to Step 11

10

Replace the lamp.

Is the repair complete?

--

Go to Step 16

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11

Connect a test lamp from terminal A to ground. Refer to Circuit Testing in wiring systems.

Does the test lamp light?

--

Go to Step 15

Go to Step 12

12

Inspect FR PRK LPS fuse in underhood fuse block. Is fuse good?

--

Go to Step 14

Go to Step 13

13

Locate and repair CKT 2309 (BRN) for an short to ground. Refer to Wiring Repairs in wiring systems.

Is the repair complete?

--

Go to Step 16

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14

Locate and repair CKT 2309 (BRN) for an open. Refer to Wiring Repairs in wiring systems.

Is the repair complete?

--

Go to Step 16

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15

Locate and repair CKT 150 (BLK) LH side and/or CKT 250 (BLK) RH side for an open. Refer to Wiring Repairs in wiring systems.

Is the repair complete?

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Go to Step 16

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16

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3