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

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 OFF the ignition.
  2. Observe the park lamps.
  3. Turn the park lamps ON and OFF.

Do the park lamps operate properly?

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

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition, with engine OFF.
  3. Place the headlamp switch in the PARK position.
  4. With the scan tool, observe the Park Lamp Switch parameter in the Body Control Module (BCM) lighting data list.

Does the Park Lamp Switch data parameter display ON?

Go to Step 5

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the C3 harness connector at the turn signal/multifunction switch.
  3. Connect a 3-amp fused jumper wire between the park lamp switch ON signal circuit and the turn signal/multifunction switch ground circuit at the turn signal/multifunction switch C3 harness connector.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the Park Lamp Switch parameter in the BCM lighting data list.

Does the Park Lamp Switch data parameter display ON?

Go to Step 11

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Disconnect the park lamp relay. Refer to Relay Replacement in Wiring Systems.
  3. Connect a test lamp between the park lamp relay control circuit and the park lamp relay coil side supply voltage circuit at the underhood fuse block.
  4. Turn ON the ignition, with the engine OFF.
  5. Turn the park lamps ON and OFF with the turn signal/multifunction switch.

Does the test lamp turn ON and OFF as the turn signal/multifunction switch is cycled?

Go to Step 9

Go to Step 6

6

Test the park lamp relay control circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 13

7

Locate and repair an open or high resistance in the turn signal/multifunction switch ground 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 8

8

Locate and repair an open, high resistance, or short to voltage in the park lamp switch ON signal 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 13

9

  1. Turn OFF the ignition.
  2. Connect a 10-amp fused jumper between the park lamp relay switch side supply voltage circuit and the park lamp supply voltage circuit.
  3. Turn ON the ignition, with the engine OFF.

Do all of the park lamps illuminate?

Go to Step 12

Go to Step 10

10

Locate and repair an open, high resistance, or short to ground in the inoperative park lamp supply voltage 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 14

11

Inspect for poor connections at the harness connector of the turn signal/multifunction switch. 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

12

Inspect for poor connections at the park lamp 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

13

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 17

14

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

Did you complete the repair?

Go to Step 18

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15

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 18

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16

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

Did you complete the replacement?

Go to Step 18

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17

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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18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2