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

Verify that the park, license, and tail lamps are inoperative.

Do the park, license, and tail lamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are all park, license, and tail lamps inoperative?

Go to Step 6

Go to Step 4

4

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

Did you find and correct the condition?

Go to Step 19

Go to Step 5

5

Test the ground circuit of the inoperative lamp for high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 15

6

The PK LP relay is located on the reverse side of the I/P fuse block.

  1. Remove the PK LP relay.
  2. Install a jumper between the coil side supply circuit and the switch side circuit of the PK LP relay.

Do the park lamps illuminate?

Go to Step 7

Go to Step 14

7

  1. Remove the jumper.
  2. Reinstall the PK LP relay.
  3. Disconnect the body control module (BCM) connector C1.
  4. At the BCM connector, install a jumper between the park lamp relay control circuit and ground.

Do the park lamps illuminate?

Go to Step 9

Go to Step 8

8

Test for a poor connection or a short to battery positive voltage open in the park lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 16

9

  1. Reconnect the BCM connector C1.
  2. Disconnect the lamp switch assembly.
  3. At the lamp switch assembly connector, install a jumper between the park lamp switch ON signal circuit and ground.

Do the park lamps illuminate?

Go to Step 10

Go to Step 12

10

Test for a short to ground in the exterior lamps OFF input circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 11

11

Inspect for poor connections at the harness connector of the multifunction turn signal switch. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 17

12

Test for a poor connection, an open, or a short to battery positive in the park lamp switch on the signal circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 13

13

Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 18

14

Repair a short to ground, an open, or a poor connection in the park lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 19

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15

Replace the inoperative bulb.

Did you complete the replacement?

Go to Step 19

--

16

Replace the PK LP relay. Refer to Relay Replacement .

Did you complete the repair?

Go to Step 19

--

17

Replace the lamp switch assembly. Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 19

--

18

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3