GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Master Electrical Component List

DEFINITION: The instrument panel (I/P) courtesy dome and roof rail courtesy lamps are ON at all times.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Ensure the instrument panel dimmer switch is not in the DOME position.
  2. Close all of the vehicle doors.
  3. Wait 20 seconds.

Are the courtesy lamps illuminated?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

Use the scan tool in order to command the courtesy lamps OFF.

Do the courtesy lamps turn OFF?

Go to Step 4

Go to Step 6

4

  1. Close all of the vehicle doors.
  2. With a scan tool, observe the Driver Door Open Sw. and the Passenger Door Open Sw. parameters in the Lamp Status data list.

Does the scan tool indicate that all parameters are OFF?

Go to Step 14

Go to Step 5

5

Does the scan tool indicate that the Driver Door Open Sw. parameter is ON?

Go to Step 9

Go to Step 10

6

Disconnect the lamp switch assembly.

Are the courtesy lamps illuminated?

Go to Step 7

Go to Step 13

7

Test for a short to ground in the courtesy lamp switch ON signal circuit of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 8

8

  1. Disconnect the BCM connector C1.
  2. Test the courtesy lamp supply voltage circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 14

9

  1. Disconnect the driver door lock switch.
  2. Observe the Driver Door Open Sw. parameter as you disconnect the switch.

Does the scan tool indicate that the Driver Door Open Sw. parameter is OFF when the driver door lock switch is disconnected?

Go to Step 16

Go to Step 11

10

  1. Disconnect the passenger door lock switches one at a time.
  2. Observe the Passenger Door Open Sw. parameter as you disconnect each switch.

Does the scan tool indicate that the Passenger Door Open Sw. parameter is OFF when one of the passenger door lock switches is disconnected?

Go to Step 16

Go to Step 12

11

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

Did you find and correct the condition?

Go to Step 18

Go to Step 14

12

Test the passenger door open switch signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 14

13

Inspect for poor connections at the harness connector of the lamp switch assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 15

14

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 17

15

Replace the lamp switch assembly. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 18

--

16

Replace the inoperative door lock switch. Refer to Front Side Door Lock Replacement or to Rear Door Lock Replacement .

Did you complete the replacement?

Go to Step 18

--

17

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2