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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 951 (LIGHTING SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESINTERIOR BACKLIGHTING INOPERATIVE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Interior Backlighting Inoperative

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Interior Backlighting Inoperative
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Interior Backlighting Inoperative

Step Action Yes No
Schematic Reference:  Interior Lights Dimming Schematics   or  Body Control System Schematics 
Connector End View Reference: Lighting Systems Connector End Views  or Body Control System Connector End Views in Body Control System.
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 interior backlighting is inoperative.
Does the interior backlighting operate normally?		 Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 Are all of the interior backlighting lamps inoperative? Go to Step 5  Go to Step 4 
4 Test for an open or high resistance in the following circuits of the inoperative lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  • The instrument panel lamps dimming control
  • The LED dimming supply
  • The ground

Did you find and correct a condition?		 Go to Step 13  Go to Step 8 
5 Is the TBC 2A Fuse in the I/P fuse block open? Go to Step 6  Go to Step 7 
6 Test the battery positive voltage circuit of the BCM for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 10 
7 Test for the following conditions. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  • Short to voltage in the dimmer potentiometer low reference circuit of the BCM.
  • High resistance or an open in the LED dimming signal circuit of the BCM.
  • Short to ground in the LED dimming signal circuit of the BCM.

Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
8 Inspect for poor connections at the harness connector of the affected lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 11 
9 Inspect for poor connections at the harness connector of the body control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 12 
10 Repair the controls illumination lamps dimming control circuit for a short to ground. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 13  -
11 Replace the affected lamp or internal lamp component.
Did you complete the replacement?		 Go to Step 13  -
12
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 13  -
13 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 3 
RENDER: 1.0x

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