GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Verify that the headlamp switch is in the OFF position.

Do either the marker, license or tail lamps remain illuminated?

Go to Step 3

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

3

With a scan tool, observe the Park Lamp parameter in the Dash Integration Module (DIM) inputs data list.

Does the scan tool indicate that the Park Lamp parameter is off?

Go to Step 4

Go to Step 7

4

With a scan tool, observe the Park Lamp Relay Output parameter in the Dash Integration Module (DIM) outputs data list.

Does the scan tool indicate that the Park Lamp Relay Output parameter is off?

Go to Step 5

Go to Step 15

5

  1. Turn OFF the ignition.
  2. Disconnect the PRK LP relay.
  3. Turn ON the ignition, with the engine off.

Did the lamps turn off?

Go to Step 6

Go to Step 8

6

Connect a test lamp between the supply voltage circuit of the PRK LP relay coil and the control circuit of the PRK LP relay.

Does the test lamp illuminate?

Go to Step 12

Go to Step 14

7

  1. Turn OFF the ignition.
  2. Disconnect the headlamp switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Park Lamp parameter.

Does the scan tool indicate that the Park Lamp parameter is off?

Go to Step 13

Go to Step 11

8

  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the DIM (C3).
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the backlight lamps control circuit and a good ground.

Does the test lamp illuminate?

Go to Step 19

Go to Step 9

9

  1. Turn OFF the ignition.
  2. Reconnect the harness connector of the DIM (C3).
  3. Turn ON the ignition, with the engine OFF.
  4. Disconnect the LP PK R fuse.

Do any of the lamps powered by the LP PK R fuse remain on?

Go to Step 16

Go to Step 10

10

Disconnect the LP PK L fuse.

Do any of the lamps powered by the LP PK L fuse remain on?

Go to Step 17

Go to Step 18

11

Test for a short to ground 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 23

Go to Step 15

12

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

Did you find and correct the condition?

Go to Step 23

Go to Step 15

13

Inspect for poor connections at the harness connector of the headlamp 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 23

Go to Step 20

14

Inspect for poor connections at the PRK LP 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 23

Go to Step 21

15

Inspect for poor connections at the harness connector of the Dash Integration Module (DIM). 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 23

Go to Step 22

16

Repair a short to voltage in the right park lamp supply voltage circuit.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

17

Repair a short to voltage in the left park lamp supply voltage circuit.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

18

Repair a short to voltage in the instrument panel lamp fuse supply voltage-1 circuit.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

19

Repair a short to battery positive voltage in the backlight lamps control circuit.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

20

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 23

--

21

Replace the PRK LP relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 23

--

22

Important:: Perform the setup procedure for the Dash Integration Module (DIM). Refer to Body Control Module (BCM) Programming/RPO Configuration .

Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 23

--

23

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2