GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior 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 all of the doors are closed properly.
  3. Place the interior lamp switch in the OFF position.

Do the courtesy 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 all of the Dome/Buzzer Switch parameters in the drivers door module (DDM) Inputs data list.

Does the scan tool indicate that any of the Dome/Buzzer Switch parameters are ON?

Go to Step 12

Go to Step 4

4

Are only the interior lamps controlled by the FRT CTSY relay ON?

Go to Step 6

Go to Step 5

5

Are only the interior lamps controlled by the RR CTSY relay ON?

Go to Step 8

Go to Step 10

6

  1. Turn OFF the ignition.
  2. Disconnect the FRT CTSY relay.
  3. Turn ON the ignition, with the engine OFF.

Do the courtesy lamps remain illuminated?

Go to Step 23

Go to Step 7

7

Connect a test lamp between the battery positive voltage circuit of the FRT CTSY relay coil and the control circuit of the FRT CTSY relay.

Does the test lamp illuminate?

Go to Step 13

Go to Step 17

8

  1. Turn OFF the ignition.
  2. Disconnect the RR CTSY relay.
  3. Turn ON the ignition, with the engine OFF.

Do the courtesy lamps remain illuminated?

Go to Step 23

Go to Step 8

9

Connect a test lamp between the battery positive voltage circuit of the RR CTSY relay coil and the control circuit of the RR CTSY relay.

Does the test lamp illuminate?

Go to Step 14

Go to Step 17

10

With a scan tool, observe the Interior Lamp Switch parameter in the instrument panel module (IPM) Non - HVAC data list.

Does the scan tool display ON?

Go to Step 11

Go to Step 22

11

  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the overhead console.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Interior Lamp Switch parameter.

Does the scan tool display ON?

Go to Step 16

Go to Step 20

12

  1. Turn OFF the ignition.
  2. Disconnect the appropriate door jamb switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate Dome/Buzzer Switch parameter.

Does the scan tool display ON?

Go to Step 15

Go to Step 18

13

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

Did you find and correct the condition?

Go to Step 30

Go to Step 21

14

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

Did you find and correct the condition?

Go to Step 30

Go to Step 21

15

Test the door open switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 30

Go to Step 19

16

Test the interior lamp switch on signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 30

Go to Step 22

17

Inspect for poor connections at the appropriate CTSY 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 30

Go to Step 24

18

Inspect for poor connections at the harness connector of the appropriate 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 30

Go to Step 25

19

Inspect for poor connections at the harness connector of the appropriate door module. 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 30

Go to Step 26

20

Inspect for poor connections at the harness connector of the overhead console. 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 30

Go to Step 27

21

Inspect for poor connections at the harness connector of the RIM. 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 30

Go to Step 28

22

Inspect for poor connections at the harness connector of the IPM. 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 30

Go to Step 29

23

Repair a short to ground in the appropriate interior lamp control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 30

--

24

Replace the appropriate CTSY relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 30

--

25

Replace the appropriate door jamb switch. Refer to Front Side Door Latch Replacement and Rear Side Door Latch Replacement in Doors.

Did you complete the replacement?

Go to Step 30

--

26

Replace the appropriate door module. Refer to Door Control Module Replacement in Doors.

Did you complete the replacement?

Go to Step 30

--

27

Replace the overhead console. Refer to Roof Console Replacement in Interior Trim.

Did you complete the replacement?

Go to Step 30

--

28

Important:: Perform the setup procedure for the Rear Integration Module (RIM).

Replace the RIM. Refer to Rear Integration Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 30

--

29

Important:: Perform the setup procedure for the Instrument Panel Integration Module (IPM).

Replace the IPM. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 30

--

30

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2