Courtesy Lamps Always On. Chevrolet TrailBlazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2004 🢒 TrailBlazer - 2WD 🢒 Accessories 🢒 Theft Deterrent 🢒 Courtesy Lamps Always On

Step

Action

Yes

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views , Body Control System Connector End Views in Body Control System , or Power Door Systems Connector End Views in Doors

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Verify that the courtesy/dome lamps are always ON.

Do the courtesy/dome lamps operate normally?

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

Go to Step 3

Inspect for the following related body control module (BCM), driver door module (DDM), passenger door module (PDM), and lift gate (LGM) or end gate (EGM) module data parameters. Refer to Scan Tool Data List and Scan Tool Data Definitions for typical values and definitions:

•	The courtesy lamp switch

•	The interior lamp defeat switch

•	The door ajar switches

•	The liftglass ajar switch

•	The liftgate ajar switch

•	The upper left dome lamp switch

Was a problem found?

Go to Step 4

Go to Step 8

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.

Is continuity present?

Go to Step 5

Go to Step 6

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 12

Go to Step 7

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 12

Go to Step 9

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

Did you find and correct the condition?

Go to Step 12

Go to Step 10

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 12

Go to Step 11

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

•	Headlamp Switch Replacement

•	Front Side Door Latch Replacement in Doors

•	Rear Side Door Latch Replacement in Doors

•	Liftgate Window Latch Replacement in Body Rear End

•	Liftgate Latch Replacement in Body Rear End

•	Endgate Latch Replacement - Left Side Upper in Body Rear End

Did you complete the replacement?

Go to Step 12

Important: Perform the setup procedure for the replacement module as applicable.

Replace the module in the affected circuit. Refer to the appropriate replacement procedure:

•	Door Lock and Side Window Switch Replacement - Driver Side in Doors

•	Door Lock and Side Window Switch Replacement - Passenger Side in Doors

•	Liftgate Control Module Replacement in Body Rear End

•	Rear Body Control Module Replacement - Endgate in Body Rear End

Did you complete the replacement?

Go to Step 12

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3