GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Probe the marker lamp supply voltage circuit of the trailer tow connector with a test lamp that is connected to ground.
  2. Place the headlamp switch in the PARK position.
  3. Place the marker lamps defeat switch in the enable position.

Does the test lamp illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the vehicles marker lamps operate properly?

Go to Step 4

Go to Marker Lamps Inoperative

4

Repair the following in the marker lamp supply voltage circuit:

    • An open
    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 5

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5

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2