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 1579 (LIGHTING SYSTEMS)
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Section 1579 (Lighting Systems)
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Section 1579 (Lighting Systems)
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. 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
- DTC B0951: Headlamp On Indicator Control Circuit
- DTC B1480: Inadvertent Power Supply Voltage Circuit
- DTC B2527: Front Fog Lamp Switch Signal Circuit Is Shorted To Ground
- DTC B2530: Front Fog Lamp Relay Control Circuit
- DTC B2540: Rear Fog Lamp Relay Control Circuit
- DTC B2550: Backup Lamp Supply Voltage Circuit
- DTC B2575: Headlamp Low Beam Relay Control Circuit
- DTC B2580: High Beam Headlamp Relay Control Circuit
- DTC B2585: Park Lamp Relay Control Circuit
- DTC B2600: DRL Relay Control Circuit
- DTC B2610: Dimming Control Circuit
- DTC B2615: Courtesy Lamp Supply Voltage
- DTC B2620: Dimming Input Voltage
- DTC B2625: LED Dimming Signal Circuit Is Shorted To Ground
- DTC B2645: Ambient Light Sensor Signal Voltage
- DTC B3801: Courtesy/Dome Lamps
- DTC B3802: BCM Receives Headlamps ON Signal Request Without A Park Lamp ON Signal Request
- Symptoms-Lighting Systems
- Backup Lamps Always On
- Backup Lamps Inoperative
- Cargo Lamp Always On
- Cargo Lamp Inoperative
- Clearance Lamps Inoperative
- Courtesy Lamps Always On
- Courtesy Lamps Inoperative
- Daytime Running Lamps (DRL) Always On
- Daytime Running Lamps (DRL) Inoperative
- Exterior Courtesy Lamp(s) Always On
- Exterior Courtesy Lamp(s) Inoperative
- Fog Lamp Indicator Inoperative
- Fog Lamp Indicator Inoperative-Rear
- Fog Lamps Always On
- Fog Lamps Inoperative
- Fog Lamps Always On-Rear
- Fog Lamps Inoperative-Rear
- Hazard Lamps Always On
- Hazard Lamps Inoperative
- Headlamps Always On-Low or High Beam
- Headlamps Inoperative-High Beams
- Headlamps Inoperative-Low Beams
- Headlamps Inoperative-Low and High Beams
- Headlamps Inoperative-Flash to Pass
- 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
- Park, License, and Tail Lamps Always On
- Park, License, and Tail Lamps Inoperative
- Reading Lamp(s) Inoperative
- Roof Beacon Lamp Always On
- Roof Beacon Lamp 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
- Vanity Mirror Lamp(s) Inoperative
- Repair Instructions
- Stop Lamp Switch Replacement
- Headlamp Switch Replacement
- Headlamp Leveling Switch Replacement
- Lamp Switch Assembly Replacement-Front Fog Lamp and Cargo Lamp
- Fog Lamp Switch Replacement-Rear
- Ambient Light Sensor Replacement
- Hazard and Turn Signal Flasher Replacement
- Courtesy Lamp Replacement-Exterior
- Courtesy Lamp/Reflector Replacement-Door
- Instrument Panel (I/P) Compartment Lamp Switch Replacement
- Dome Lamp Replacement
- Underhood Lamp Replacement
- Headlamp Assembly or Headlamp Bulb Replacement (Old Style)
- Headlamp Assembly or Headlamp Bulb Replacement (New Style GMC)
- Headlamp Assembly or Headlamp Bulb Replacement (New Style Chevy)
- Headlamp Aiming
- Fog Lamp Replacement-Front (Old Style)
- Fog Lamp Replacement-Front (New Style GMC)
- Fog Lamp Replacement-Front (New Style Chevrolet)
- Fog Lamp Bulb Replacement-Front (Old Style)
- Fog Lamp Bulb Replacement-Front (New Style GMC)
- Fog Lamp Bulb Replacement-Front (New Style Chevrolet)
- Fog Lamp Bulb Replacement-Rear
- Fog Lamp Aiming Procedure
- Park/Turn Signal Lamp Replacement (Old Style)
- Park/Turn Signal Lamp Replacement (New Style)
- Marker Lamp Replacement-Roof (Center)
- Marker Lamp Replacement-Roof (Outer)
- Marker Lamp Bulb Replacement-Roof (Center)
- Marker Lamp Bulb Replacement-Roof (Outer)
- High Mounted Stop Lamp Replacement
- License Lamp Replacement (Pickup W/O Bumper)
- Tail/Turn Signal Lamp Replacement (Except Stepside)
- Tail/Turn Signal Lamp Replacement (Stepside)
- 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.