GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 Seville 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 Courtesy Lamps Inoperative

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 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. Cover the ambient light sensor.
  3. Open and Close all of the doors.
  4. Position the courtesy lamp switch to the ON, OFF, and AUTO positions.

Do the courtesy lamps operate properly?

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

Go to Step 3

3

Are all of the courtesy lamps inoperative?

Go to Step 4

Go to Step 5

4

Are the courtesy lamps only inoperative with the door(s)?

Go to Step 15

Go to Step 7

5

Is there only one inoperative lamp?

Go to Step 18

Go to Step 6

6

With a scan tool, command the FRT CTSY relay On.

Are the courtesy lamps operated by the FRT CTSY relay inoperative?

Go to Step 24

Go to Step 29

7
  1. Place the interior lamp switch in the ON position.
  2. With a scan tool, observe the Interior Lamp Switch parameter in the Instrument Panel Integration Module (IPM) inputs data list.

Does the scan tool display ON?

Go to Step 11

Go to Step 8

8

Does the scan tool display OFF?

Go to Step 34

Go to Step 9

9
  1. Disconnect the overhead console.
  2. Connect a 3-amp fused jumper between the interior lamp switch on signal circuit and a good ground.
  3. With a scan tool, observe the Interior Lamp Switch parameter in the IPM data list.

Does the scan tool display ON?

Go to Step 10

Go to Step 34

10

Connect a 3-amp fused jumper between the interior lamp switch on signal circuit and the ground circuit of the interior lamp switch.

Does the scan tool display ON?

Go to Step 44

Go to Step 49

11
  1. Place the interior lamp switch in the OFF position.
  2. With a scan tool, observe the Interior Lamp Switch parameter in IPM data list.

Does the scan tool display OFF?

Go to Step 14

Go to Step 12

12
  1. Connect a 3 amp fused jumper between the interior lamp switch off signal circuit and a good ground.
  2. With a scan tool, observe the Interior Lamp Switch parameter in IPM data list.

Does the scan tool display OFF?

Go to Step 13

Go to Step 34

13

Connect a 3-amp fused jumper between the interior lamp switch off signal circuit and the ground circuit of the interior lamp switch.

Does the scan tool display OFF?

Go to Step 44

Go to Step 49

14

Place the interior lamp switch in the AUTO position.

Does the scan tool display AUTO?

Go to Step 20

Go to Step 34

15
  1. Open all the doors.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe all the Dome/Buzzer Sw. parameters in the drivers door module (DDM) inputs data list.

Does the scan tool indicate that all of the Dome/Buzzer Sw. parameters are ON?

Go to Step 43

Go to Step  16

16
  1. Turn OFF the ignition.
  2. Disconnect the inoperative door jamb switch.
  3. Connect a 3-amp fused jumper between the door latch switch signal circuit and a good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the Dome/Buzzer Sw. parameter.

Does the scan tool indicate that the Dome/Buzzer Sw. parameter is ON?

Go to Step 17

Go to Step 36

17
  1. Connect a 3 amp fused jumper between the door latch switch signal circuit and the door jamb switch ground circuit.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Dome/Buzzer Sw. parameter.

Does the scan tool indicate that the Dome/Buzzer Sw. parameter is ON?

Go to Step 42

Go to Step 48

18
  1. Remove the inoperative courtesy lamp bulb(s).
  2. Connect a test lamp between the supply voltage circuit of the inoperative courtesy lamp and a good ground.

Does the test lamp illuminate?

Go to Step 19

Go to Step 51

19

Connect a test lamp between the supply voltage circuit of the inoperative courtesy lamp and the ground circuit of the inoperative courtesy lamp.

Does the test lamp illuminate?

Go to Step 47

Go to Step 50

20
  1. Turn OFF the ignition.
  2. Disconnect the INT LP relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the INT LP relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 21

Go to Step 52

21

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

Does the test lamp illuminate?

Go to Step 22

Go to Step 39

22

Connect a test lamp between the battery positive voltage circuit of the INT LP switch and a good ground.

Does the test lamp illuminate?

Go to Step 23

Go to Step 53

23

Connect a 10-amp fused jumper between the battery positive voltage circuit of the INT LP switch and the courtesy lamp supply voltage circuit.

Do the courtesy lamps operate properly?

Go to Step 40

Go to Step 51

24

With a scan tool, command the FRT CTSY relay ON and OFF.

Do you hear a click when you command the FRT CTSY relay ON and OFF?

Go to Step 27

Go to Step 25

25
  1. Turn OFF the ignition.
  2. Disconnect the FRT CTSY relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the FRT CTSY relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 26

Go to Step 54

26
  1. 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.
  2. With a scan tool, command the FRT CTSY relay ON.

Does the test lamp illuminate?

Go to Step 41

Go to Step 37

27
  1. Turn OFF the ignition.
  2. Disconnect the FRT CTSY relay.
  3. Connect a test lamp between the battery positive voltage circuit of the FRT CTSY relay coil and the ground circuit of the FRT CTSY relay switch.

Does the test lamp illuminate?

Go to Step 28

Go to Step 55

28

Connect a 10-amp fused jumper between the ground circuit of the FRT CTSY relay switch and the interior lamp control circuit.

Do the interior lamps illuminate?

Go to Step 41

Go to Step 58

29

With a scan tool, command the RR CTSY relay ON and OFF.

Do you hear a click when you command the RR CTSY relay ON and OFF?

Go to Step 32

Go to Step 30

30
  1. Turn OFF the ignition.
  2. Disconnect the RR CTSY relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the RR CTSY relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 31

Go to Step 56

31
  1. 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.
  2. With a scan tool, command the RR CTSY relay ON.

Does the test lamp illuminate?

Go to Step 41

Go to Step 38

32
  1. Turn OFF the ignition.
  2. Disconnect the RR CTSY relay.
  3. Connect a test lamp between the battery positive voltage circuit of the RR CTSY relay coil and the ground circuit of the RR CTSY relay switch.

Does the test lamp illuminate?

Go to Step 33

Go to Step 57

33

Connect a 10-amp fused jumper between the ground circuit of the RR CTSY relay switch and the courtesy lamp switch signal circuit.

Do the interior lamps illuminate?

Go to Step 41

Go to Step 59

34

Test the interior lamp switch lamp off signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 68

Go to Step 45

35

Test the interior lamp switch on signal circuit for high resistance, 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 68

Go to Step 46

36

Test the inoperative door latch 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 68

Go to Step 43

37

Test for an open or high resistance in the control circuit of the FRT CTSY relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 68

Go to Step 46

38

Test for an open or high resistance in the control circuit of the RR CTSY relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 68

Go to Step 46

39

Test for an open or high resistance in the control circuit of the INT LP relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 68

Go to Step 46

40

Inspect for poor connections at the INT 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 68

Go to Step 60

41

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 68

Go to Step 61

42

Inspect for poor connections at the harness connector of the inoperative 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 68

Go to Step 62

43

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 68

Go to Step 63

44

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 68

Go to Step 64

45

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 68

Go to Step 65

46

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 68

Go to Step 66

47

Inspect for poor connections at the harness connector of the inoperative courtesy lamp. 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 68

Go to Step 67

48

Repair an open or high resistance in the inoperative door latch switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

49

Repair an open or high resistance in the interior lamp switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

50

Repair the high resistance or open in the ground circuit of the inoperative courtesy lamp. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

51

Repair the high resistance or open in the supply voltage circuit of the courtesy lamps. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

52

Repair the high resistance or open in the battery positive voltage circuit of the INT LP relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

53

Repair the open or high resistance in the battery positive voltage circuit of the INT LP relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

54

Repair the open or high resistance in the battery positive voltage circuit of the FRT CTSY relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

55

Repair the open or high resistance in the ground circuit of the FRT CTSY relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

56

Repair the open or high resistance in the battery positive voltage circuit of the RR CTSY relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

57

Repair the open or high resistance in the ground circuit of the RR CTSY relay switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

58

Repair the open or high resistance in the interior lamp control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

59

Repair the open or high resistance in the courtesy lamp switch signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 68

--

60

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

Did you complete the replacement?

Go to Step 68

--

61

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

Did you complete the replacement?

Go to Step 68

--

62

Replace the inoperative 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 68

--

63

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

Did you complete the replacement?

Go to Step 68

--

64

Replace interior lamp switch. Refer to Roof Console Replacement in Interior Trim.

Did you complete the replacement?

Go to Step 68

--

65

Important:: Perform the setup procedure for the IPM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

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

Did you complete the replacement?

Go to Step 68

--

66

Important:: 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 68

--

67

Replace the inoperative courtesy lamp. Refer to one of the following:

    •  Door Lamp Replacement
    •  Dome Lamp Replacement

Did you complete the replacement?

Go to Step 68

--

68

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2