GM Service Manual Online
For 1990-2009 cars only

Courtesy Lamps Inoperative From I/P Dimmer Switch

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

DEFINITION: Courtesy lamps are inoperative from the instrument panel dimmer switch only.

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. Close all of the vehicle doors.
  2. Wait 10 seconds.
  3. Place the instrument panel dimmer switch in the DOME position.

Do the courtesy lamps illuminate?

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

Go to Step 3

3

  1. Disconnect the instrument panel dimmer switch.
  2. Connect a 10-amp fused jumper wire between the courtesy lamp low control circuit of the instrument panel dimmer switch and a good ground.

Do the courtesy lamps illuminate?

Go to Step 4

Go to Step 5

4

Inspect for poor connections at the harness connector of the instrument panel dimmer 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 7

Go to Step 6

5

Repair an open or high resistance in the courtesy lamp low control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 7

--

6

Replace the instrument panel dimmer switch. Refer to Instrument Panel Lamp Dimmer Switch Replacement .

Did you complete the replacement?

Go to Step 7

--

7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Courtesy Lamps Inoperative From Door Switch

Step

Action

Yes

No

Schematic Reference: Interior 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

Open each door of the vehicle, one at a time, using the following procedure:

  1. Open the vehicle door.
  2. Observe the courtesy lamps.
  3. Close the vehicle door.
  4. Wait 10 seconds.

Do the courtesy lamps illuminate when each door is opened?

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

Go to Step 3

3

Are the courtesy lamps inoperative from all of the doors?

Go to Step 4

Go to Step 6

4

Place the dome lamp in the ON position.

Does the dome lamp illuminate?

Go to Step 10

Go to Step 5

5

  1. Disconnect the body control module (BCM).
  2. Probe the battery positive voltage circuit of the BCM with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 12

6

Are the courtesy lamps inoperative from the driver door?

Go to Step 8

Go to Step 7

7

Are the courtesy lamps inoperative from all of the passenger doors?

Go to Step 13

Go to Step 9

8

  1. Close all of the vehicles doors, except the driver's.
  2. Disconnect the driver door ajar switch. Refer to Door Lock Replacement in Doors.
  3. Connect a 3-amp fused jumper wire between the driver door ajar switch signal circuit and a good ground.

Do the courtesy lamps illuminate?

Go to Step 14

Go to Step 15

9

  1. Close all of the vehicles doors, except the inoperative door.
  2. Disconnect the inoperative door ajar switch or door jamb switch. Refer to Rear Door Jamb Switch Replacement or Door Lock Replacement in Doors.
  3. Connect a 3-amp fused jumper wire between the appropriate door ajar switch signal circuit and a good ground.

Do the courtesy lamps illuminate?

Go to Step 14

Go to Step 15

10

Test the courtesy lamp low control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 17

11

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

Did you find and correct the condition?

Go to Step 21

Go to Step 17

12

Test the battery positive voltage circuit of the BCM for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 18

13

Test the passenger door ajar switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 17

14

Test the ground circuit of the inoperative door ajar switch or door jamb switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 16

15

Test the inoperative door ajar switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 17

16

Inspect for poor connections at the harness connector of the inoperative door ajar switch or door jamb 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 21

Go to Step 19

17

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 21

Go to Step 20

18

Repair a short to ground in the courtesy lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 21

--

19

Replace the inoperative door ajar switch or door jamb switch. Refer to Rear Door Jamb Switch Replacement or Door Lock Replacement in Doors.

Did you complete the replacement?

Go to Step 21

--

20

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 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3