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. Install the scan tool.
  2. Turn ON the ignition, with engine OFF.
  3. Place the headlamp switch in the OFF position.
  4. With the scan tool, observe the Park Lamp Switch parameter in the IPM inputs data list.

Does the Park Lamp Switch data parameter display OFF?

Go to Step 4

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the C3 harness connector at the turn signal/multifunction switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Park Lamp Switch parameter in the IPM inputs data list.

Does the Park Lamp Switch data parameter display OFF?

Go to Step 8

Go to Step 7

4

  1. Turn OFF the ignition.
  2. Disconnect the park lamp relay. Refer to Relay Replacement .
  3. Turn ON the ignition, with the engine OFF.

Do the park lamps turn OFF?

Go to Step 5

Go to Step 11

5

  1. Turn OFF the ignition.
  2. 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.
  3. Turn ON the ignition, with the engine OFF.
  4. Turn On the park lamps.

Does the test lamp illuminate?

Go to Step 9

Go to Step 6

6

Test the park lamp relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 10

7

Test the park lamp switch on signal circuit of the turn signal/multifunction switch for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 10

8

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 .

Did you find and correct the condition?

Go to Step 17

Go to Step 14

9

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

Did you find and correct the condition?

Go to Step 17

Go to Step 15

10

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

Did you find and correct the condition?

Go to Step 17

Go to Step 16

11

Locate and repair a short to voltage in the park lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 12

12

Inspect for poor connections at the harness connector of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 13

13

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement .

Did you complete the replacement?

Go to Step 17

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14

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement .

Did you complete the replacement?

Go to Step 17

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15

Replace the park lamp relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 17

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16

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

Did you complete the replacement?

Go to Step 17

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17

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2