GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

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

Do the park lamps illuminate?

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

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 4

Go to Step 5

4

  1. Disconnect the inoperative lamp.
  2. Probe the park lamp supply voltage circuit of the inoperative lamp with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 13

5

With a scan tool, command the park lamps ON.

Do the park lamps illuminate?

Go to Step 6

Go to Step 7

6

  1. Place the headlamp switch in the OFF position.
  2. Turn OFF the ignition.
  3. Disconnect the body control module (BCM).
  4. Place the headlamp switch in the PARK position.
  5. Probe the park lamp switch ON input circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

7

  1. Disconnect the auto park lamp control relay.
  2. Connect a 15-amp fused jumper wire between the switch side battery positive voltage circuit of the auto park lamp control relay and the park lamp supply voltage circuit of the auto park lamp control relay.

Do the park lamps illuminate?

Go to Step 10

Go to Step 14

8

Test for an open or high resistance in the park lamp switch ON input circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 11

9

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 15

10

Inspect for poor connections at the auto park lamp control relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

11

Inspect for poor connections at the harness connector of the turn/headlamp wiper switch assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

12

Repair an open or high resistance in the ground circuit of the inoperative park lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

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13

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

Did you complete the repair?

Go to Step 18

--

14

Repair an open or high resistance in the park lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

15

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 18

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16

Replace the auto park lamp control relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 18

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17

Replace the turn/headlamp wiper switch assembly. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3