GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Open the driver's door.

Does the system operate normally?

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

Go to Step 3

3

Do the courtesy lamps operate normally?

Go to Step  4

Go to Courtesy Lamps Inoperative

4

Are both exterior courtesy lamps inoperative?

Go to Step 5

Go to Step 8

5

  1. Turn ON the ignition, with engine OFF.
  2. With the scan tool, command the exterior courtesy lamps relay ON and OFF.

Do the exterior courtesy lamps come ON and OFF with each command?

Go to Step 10

Go to Step 6

6

  1. Disconnect the exterior courtesy lamps relay.
  2. Connect a 3 amp jumper wire between the battery positive voltage circuit and the exterior courtesy lamps supply voltage circuit of the exterior courtesy lamps relay.

Do the exterior courtesy lamps illuminate?

Go to Step 11

Go to Step 7

7

Inspect for poor connections at the body wiring harness junction block.

Did you find and correct the condition?

Go to Step 17

Go to Step 8

8

Inspect the bulb(s).

Is the filament(s) open?

Go to Step 12

Go to Step 9

9

Test the exterior courtesy lamps supply voltage circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 17

Go to Step 13

10

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 17

Go to Step 12

11

Inspect for poor connections at the harness connector of the exterior courtesy lamps 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 17

Go to Step 13

12

Inspect for poor connections at the harness connector of the bulb(s). 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 17

Go to Step 14

13

Repair the open ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 17

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14

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 17

--

15

Replace the exterior courtesy lamps relay.

Did you complete the replacement?

Go to Step 17

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16

Replace the lamp(s). Refer to Outside Rearview Mirror Courtesy Lamp Replacement .

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 3