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 701 (LIGHTING SYSTEMS)
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Section 701 (Lighting Systems)
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Section 701 (Lighting Systems)
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Specifications
- Schematic & Routing Diagrams
- Component Locator
- Diagnostic Information & Procedures
- Diagnostic Starting Point - Lighting Systems
- Diagnostic System Check - Lighting Systems
- Scan Tool Data List
- Scan Tool Data Definitions
- Diagnostic Trouble Code (DTC) List
- DTC B1397: 5 Volt Reference Output Circuit Voltage Low
- DTC B1398: 5V Reference Circuit Voltage High
- DTC B1480: Courtesy Lamps Supply Voltage Circuit Voltage Low
- DTC B2527: Front Fog Lamp Switch Signal Circuit Is Shorted To Ground
- DTC B2577: Headlamp Relay Coil Supply Voltage Circuit Shorted To Ground
- DTC B2585: Interior Park Lamps Supply Voltage Circuit
- DTC B2613: Instrument Panel Lamp Supply Voltage Circuit Is Shorted To Battery Voltage
- DTC B2617: Courtesy Lamp Relay Coil Control Circuit Is Open Or Shorted To Ground
- DTC B2618: Courtesy Lamp Relay Coil Control Circuit Is Open Or Shorted To Ground
- DTC B2642: Ground Illumination Relay Control Circuit Is Open Or Shorted To Ground
- DTC B2643: Ground Illumination Relay Control Circuit Is Shorted To Battery Voltage
- DTC B2647: Ambient Light Sensor Input Voltage Low
- DTC B2648: Ambient Light Sensor Input Voltage High
- Symptoms - Lighting Systems
- Backup Lamps Always On
- Backup Lamps Inoperative
- Cargo Lamp Always On
- Cargo Lamp Inoperative
- Cargo Lamp On Indicator Always On
- Cargo Lamp On Indicator Inoperative
- Clearance Lamps Inoperative
- Courtesy Lamps Always On
- Courtesy Lamps Inoperative
- Daytime Running Lamps (DRL) Always On
- Daytime Running Lamps (DRL) Inoperative
- Daytime Running Lamps (DRL) On With Park Brake Applied
- Exterior Courtesy Lamp(s) Always On
- Exterior Courtesy Lamp(s) Inoperative
- Fog Lamp Indicator Inoperative
- Fog Lamp Indicator Inoperative - Rear (Export)
- Fog Lamps Always On
- Fog Lamps Always On - Rear (Export)
- Fog Lamps Inoperative
- Fog Lamps Inoperative - Rear (Export)
- Hazard Lamps Inoperative
- Headlamps Inoperative - Low Beams
- Headlamps Inoperative - High Beams
- Headlamps Inoperative - Low & High Beams
- Headlamps Inoperative - Flash To Pass
- Headlamps Inoperative In Low Light Conditions
- Headlamps On In Daylight Conditions
- 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
- Park Lamps Inoperative
- Reading Lamp(s) Inoperative
- Stop Lamps Always On
- Stop 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) Always On
- Vanity Mirror Lamp(s) Inoperative
- Repair Instructions
- Headlamp Switch Replacement
- Headlamp Leveling Switch Replacement
- Lamp Switch Assembly Replacement - Front Fog Lamp & Cargo Lamp
- Fog Lamp Switch Replacement - Rear
- Ambient Light Sensor Replacement
- Daytime Running Lamps (DRL) Relay Replacement
- Hazard & Turn Signal Flasher Replacement
- Courtesy Lamp Replacement - Exterior
- Console Lamp Replacement
- Courtesy Lamp/Reflector Replacement - Door
- Instrument Panel (I/P) Compartment Lamp Replacement
- Ashtray Lamp Replacement
- Dome Lamp Replacement
- Underhood Lamp Replacement
- Headlamp Assembly Or Headlamp Bulb Replacement
- Headlamp Aiming
- Fog Lamp Replacement - Front
- Fog Lamp Bulb Replacement - Front
- Fog Lamp Bulb Replacement - Rear
- Fog Lamp Aiming Procedure
- Park/Turn Signal Lamp Replacement
- Marker Lamp Replacement - Roof (Outer)
- Marker Lamp Replacement - Roof (Center)
- Marker Lamp Bulb Replacement - Roof (Center)
- Marker Lamp Bulb Replacement - Roof (Outer)
- High Mounted Stop Lamp Replacement (Pickup)
- License Lamp Replacement (Pickup W/O Bumper)
- Tail/Turn Signal Lamp Replacement (Except Stepside)
- Tail/Turn Signal Lamp Replacement (Stepside)
- Description & Operation
- Special Tools & Equipment
RENDER: 1.0x
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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.