Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1606 (LIGHTING SYSTEMS)
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Section 1606 (Lighting Systems)
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Section 1606 (Lighting Systems)
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
- Specifications
- Schematic and Routing Diagrams
- Component Locator
- Diagnostic Information and Procedures
- Diagnostic Starting Point - Lighting Systems
- Diagnostic System Check - Lighting Systems
- Scan Tool Output Controls
- Scan Tool Data List
- Scan Tool Data Definitions
- Diagnostic Trouble Code (DTC) List
- DTC B0951
- DTC B1480
- DTC B2527
- DTC B2530
- DTC B2540
- DTC B2550
- DTC B2575
- DTC B2580
- DTC B2585
- DTC B2610
- DTC B2615
- DTC B2620
- DTC B2625
- DTC B2645
- DTC B3801
- DTC B3802
- Symptoms - Lighting Systems
- Backup Lamps Always On
- Backup Lamps Inoperative
- Cornering Lamps Always On
- Cornering Lamps Inoperative
- Courtesy Lamps Always On
- Courtesy Lamps Inoperative
- Daytime Running Lamps (DRL) Inoperative
- Daytime Running Lamps (DRL) On with Park Brake Applied
- Fog Lamp Indicator Inoperative
- Fog Lamps Always On
- Fog Lamps Always On - Rear
- Fog Lamps Inoperative
- Fog Lamps Inoperative - Rear
- Hazard Lamps Always On
- Hazard Lamps Inoperative
- Headlamp Switch On Indicator Always On
- Headlamp Switch On Indicator Inoperative
- Headlamps Always On - Low or High Beam
- Headlamps Inoperative - Low Beams
- Headlamps Inoperative - High Beams
- Headlamps Inoperative - Flash to Pass
- Headlight Leveling Inoperative
- High Beam Indicator Always On
- High Beam Indicator Inoperative
- Interior Backlighting Does Not Dim
- Interior Backlighting Inoperative
- Instrument Panel (I/P) Compartment Lamp Inoperative
- Instrument Panel (I/P) Compartment Lamp Always On
- License Lamps Inoperative
- Marker Lamps Inoperative
- Memory/Heated Seat Switch Backlighting Inoperative
- Park Lamps Inoperative
- Park, License, and Tail Lamps Always On
- Park, License, and Tail Lamps Inoperative
- Stop Lamps Always On
- Stop Lamps Inoperative
- Tail Lamps Inoperative
- Turn Signal Lamps and/or Indicators Always On or Flashing
- Turn Signal Lamps and/or Indicators Inoperative
- Underhood Lamp Inoperative
- Vanity Mirror Lamp(s) Inoperative
- Repair Instructions
- Headlamp Switch Replacement
- Ambient Light Sensor Replacement
- Headlamp Driver Module (HDM) Relay Replacement
- High Beam Relay Replacement
- Fog Lamp Relay Replacement (RPO T96)
- Fog Lamp Relay Replacement (RPO T79)
- Park Lamp Relay Replacement
- Hazard and Turn Signal Flasher Replacement
- Dome and Reading Lamp Bulb Replacement
- Courtesy Lamp Replacement - Instrument Panel
- Instrument Panel (I/P) Compartment Lamp Replacement
- Vanity Mirror Lamp Bulb Replacement
- Dome Lamp Replacement
- Underhood Lamp Replacement
- Headlamp Replacement (TrailBlazer)
- Headlamp Replacement (Bravada)
- Headlamp Replacement (Envoy, Envoy XUV)
- Headlamp Bulb Replacement
- Headlamp Aiming
- Fog Lamp Replacement - Front (GMC/Chevrolet)
- Fog Lamp Replacement - Front (Oldsmobile)
- Fog Lamp Bulb Replacement - Front
- Fog Lamp Aiming Procedure
- Park/Turn Signal/Side Marker Lamp Bulb Replacement (Envoy)
- Park/Turn Signal/Side Marker Lamp Bulb Replacement (TrailBlazer)
- Park/Turn Signal/Side Marker Lamp Bulb Replacement (Bravada)
- Cornering Lamp Replacement
- Cornering Lamp Bulb Replacement (GMC)
- Cornering Lamp Bulb Replacement (Oldsmobile)
- High Mounted Stop Lamp Replacement (Envoy, Trailblazer, Rainier, Bravada)
- Backup Lamp Replacement (GMC)
- Backup Lamp Bulb Replacement (GMC)
- License Lamp Replacement
- Tail Lamp Replacement
- Tail Lamp Bulb Replacement
- Tail Lamp Circuit Board Replacement
- Side Marker Lamp Replacement (Oldsmobile)
- Description and Operation
- Special Tools and Equipment
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.