GM Service Manual Online
For 1990-2009 cars only

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Schematic Reference: Interior Lights Schematics and Door Control Module Schematics in Doors

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

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Important: The sunload sensor assembly must indicate low light conditions for the interior lamps to operate.

  1. Cover the sunload sensor assembly.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the courtesy lamps.
  4. Open and close all of the doors.
  5. Turn the interior lamp switch ON and OFF.
  6. Turn OFF the ignition.

Do the courtesy lamps operate properly?

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

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Photocell parameter in the climate control panel (CCP) Lighting data list.
  4. Cover the sunload sensor assembly.

Does the Photocell voltage change?

Go to Step 4

Go to Twilight Sentinel Inoperative

4

With a scan tool command the Courtesy Lamp 1, 2 w/o dim output ON from the rear integration module (RIM) Output Control data list.

Do all of the interior courtesy lamps turn ON?

Go to Step 6

Go to Step 5

5

Are all of the interior courtesy lamps inoperative?

Go to Step 10

Go to Step 14

6

  1. Turn the interior lamp switch ON.
  2. With a scan tool, observe the Courtesy Lamp Switch parameter in the dash integration module (DIM) Lighting data list.

Does the scan tool display ON?

Go to Step 7

Go to Step 8

7

  1. Open all the doors.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe all the Door Jamb Sw. parameters in the door modules Inputs data lists.

Does the scan tool display ON for all the door jamb sw. inputs?

Go to Step 37

Go to Step 9

8

  1. Disconnect the I/P dimmer switch.
  2. Connect a 3-amp fused jumper between the courtesy lamps switch on signal circuit of the and the interior lamp switch ground circuit.
  3. With a scan tool observe the Courtesy Lamp Switch parameter.

Does the scan tool display ON?

Go to Step 25

Go to Step 15

9

  1. Turn OFF the ignition.
  2. Disconnect the inoperative door lock actuator.
  3. Connect a 3-amp fused jumper between the door open switch signal circuit of the door lock actuator and the ground circuit of the door lock actuator.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the inoperative Door Jamb Sw. input parameter.

Does the scan tool display ON for the inoperative door jamb sw. input?

Go to Step 23

Go to Step 17

10

  1. Turn OFF the ignition.
  2. Disconnect the interior lamp relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the interior lamp relay control side supply voltage circuit with a test lamp that connected to a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 30

11

Probe the interior lamp relay switch side supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 29

12

  1. Connect a test lamp between the INT lamp relay control side supply voltage circuit and the courtesy lamp relay control circuit.
  2. With a scan tool command the Courtesy Lamp 1, 2 w/o dim output ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 13

Go to Step 21

13

  1. Connect a 10-amp fused jumper between the switch side supply voltage circuit of the INT lamp relay and the courtesy lamp supply voltage circuit of the INT lamp relay.
  2. With a scan tool, command the Courtesy Lamp 1, 2 w/o dim ON.

Do the interior lamps illuminate?

Go to Step 22

Go to Step 19

14

  1. Turn ON the courtesy lamps.
  2. Remove the inoperative courtesy lamp bulb.
  3. Connect a test lamp between the inoperative courtesy lamp supply voltage circuit and the ground circuit of the inoperative courtesy lamp.

Does the test lamp illuminate?

Go to Step 28

Go to Step 19

15

Test the courtesy lamp switch on signal circuit for high resistance, open or short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 16

16

Test the interior lamp switch ground 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 38

Go to Step 26

17

Test the inoperative door open 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 38

Go to Step 18

18

Test the inoperative door open switch ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 24

19

Test the interior lamp supply voltage circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 20

20

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

Did you find and correct the condition?

Go to Step 38

Go to Step 27

21

Test the relay control circuit for a high resistance, an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 27

22

Inspect for poor connections at the INT lamp 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 38

Go to Step 31

23

Inspect for poor connections at the harness connector of the inoperative door lock actuator. 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 38

Go to Step 32

24

Inspect for poor connections at the harness connector of the inoperative door control 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 38

Go to Step 33

25

Inspect for poor connections at the harness connector of the I/P 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 38

Go to Step 34

26

Inspect for poor connections at the harness connector of the 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 38

Go to Step 35

27

Inspect for poor connections at the harness connector of the rear integration module (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 38

Go to Step 36

28

Inspect for poor connections at the inoperative courtesy lamp bulb. 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 38

Go to Step 37

29

Repair the open, high resistance or short to ground in the switch side supply voltage circuit of the INT lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

30

Repair the high resistance or open in the control side supply voltage circuit of the INT lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

31

Replace the in INT lamp relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 38

--

32

Replace the inoperative door lock actuator. Refer to Front Side Door Latch Replacement or Rear Side Door Latch Replacement in Doors.

Did you complete the replacement?

Go to Step 38

--

33

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

Did you complete the replacement?

Go to Step 38

--

34

Replace I/P dimmer switch. Refer to Instrument Panel Lamp Dimmer Switch Replacement .

Did you complete the replacement?

Go to Step 38

--

35

Important: After replacement perform the setup procedure for the DIM.

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

Did you complete the replacement?

Go to Step 38

--

36

Important: After replacement perform the setup procedure for the RIM.

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

Did you complete the replacement?

Go to Step 38

--

37

Replace the inoperative courtesy lamp bulb.

Did you complete the replacement?

Go to Step 38

--

38

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2