GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Courtesy Lamps Inoperative

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

Verify that the courtesy lamps are inoperative.

Do the courtesy lamps operate normally?

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

Go to Step 3

3

Is only one courtesy lamp inoperative?

Go to Step 4

Go to Step 5

4
  1. Inspect the inoperative bulb/socket for an open filament and open or corroded terminals and replace or repair as necessary.
  2. If a bulb/socket problem is not found, repair the open or high resistance in the battery positive voltage circuit or courtesy lamp low control circuit to the inoperative lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

5

Inspect for the following related BCM data parameters as applicable. Refer to Scan Tool Data List and Scan Tool Data Definitions for typical values and definitions:

    • The passenger door jamb/door handle switches
    • The dome lamp switch
    • The dome override switch
    • The driver door jamb switch
    • Key-in-ignition
    • The rear door ajar
    • The liftglass/rear gate

Was a problem found?

Go to Step 6

Go to Step 8

6

Disconnect and test the switch of the affected input circuit for proper continuity in the open and closed positions. Refer to Circuit Testing in Wiring Systems.

Does the switch operate properly?

Go to Step 7

Go to Step 12

7

Test the signal and ground circuits of the affected input circuit for a short to ground, open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 13

8

Open the IP compartment.

Does the IP compartment lamp illuminate?

Go to Step 10

Go to Step 9

9

Use a fused jumper to ground the Inadvertant power relay control circuit.

Does the IP compartment lamp illuminate?

Go to Step 13

Go to Step 15

10

Use a fused jumper to ground the courtesy lamp relay control circuit.

Do the courtesy lamps illuminate?

Go to Step 13

Go to Step 11

11

Test the following circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • Courtesy lamp relay ground
    • Courtesy lamp low control

Did you find and correct the condition?

Go to Step 18

Go to Step 16

12

Inspect for poor connections at the harness connector of the affected switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

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 BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

14

Replace the switch in the affected circuit. Refer to one of the following replacement procedures as applicable:

    •  Liftgate Window Latch Replacement in Body Rear End
    •  Endgate Window Latch Replacement in Body Rear End
    •  Ignition and Key Alarm Switch Assembly - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt
    •  Ignition and Key Alarm Switch Assembly - Disassemble - Off Vehicle in Steering Wheel and Column - Standard

Did you complete the replacement?

Go to Step 18

--

15

Replace the inadvertent power relay.

Did you complete the repair?

Go to Step 18

--

16

Replace the courtesy lamp relay.

Did you complete the repair?

Go to Step 18

--

17

Important: Perform the setup procedure for the BCM.

Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System.

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 3