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 in Wiring Systems.

DEFINITION: The sidemarker lamps are inoperative on domestic vehicles. For export repeater lamps inoperative refer to Turn Signal Lamps and/or Indicators Inoperative

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition to the ON position, with the engine OFF.
  2. Place the headlamp switch in the PARK position.

Do the sidemarker lamps operate properly?

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

Go to Step 3

3

Are the front park lamps inoperative?

Go to Park Lamps Inoperative

Go to Step 4

4

Place the turn signal switch in the left and right ON position.

Are the rear turn signal lamps inoperative?

Go to Turn Signal Lamps and/or Indicators Inoperative

Go to Step 5

5

  1. Disconnect the inoperative sidemarker lamp.
  2. Using a test lamp connected to ground, probe the park lamps supply voltage circuit of the inoperative sidemarker lamp connector.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

6

  1. Insure that the turn signals are OFF.
  2. Using a test lamp connected to battery positive voltage, probe the turn lamp supply voltage circuit of the inoperative sidemarker lamp connector.

Does the test lamp illuminate?

Go to Step 12

Go to Step 7

7

Using a test lamp connected to battery positive voltage, probe the turn lamp supply voltage circuit of the underhood junction block connector.

Does the test lamp illuminate?

Go to Step 9

Go to Step 10

8

Test for an open or high resistance in the park lamps supply voltage circuit of the inoperative sidemarker lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Test an open or high resistance in the turn lamp supply voltage circuit of the sidemarker lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

10

Repair the open or high resistance in the turn lamp supply voltage circuit of the underhood junction block connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

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11

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

Did you complete the repair?

Go to Step 13

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12

Replace the inoperative sidemarker lamp. Refer to Park/Turn Signal/Side Marker Lamp Replacement .

Did you complete the repair?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2