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.
2003 Hummer H2FACTORY OEM SERVICE PROCEDURE
Section 356 (Lighting Systems)
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
- Specifications
- Schematic and Routing Diagrams
- Lighting Systems Schematic Icons
- Headlights/Daytime Running Lights (DRL) Schematics (Headlamp Switch and Sunload Sensor Assembly)
- Fog Lights Schematics (Front)
- Exterior Lights Schematics (Turn Signal/Hazard Flasher Module Inputs)
- Interior Lights Schematics (Interior and Front Courtesy Lamp Relays)
- Interior Lights Dimming Schematics (Dimming Control)
- 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 B2556: Interior Lamp Rheostat Circuit Range
- DTC B2641: Delayed Exterior Lighting Ctrl CKT Range
- DTC B2646: Ambient Light Sensor Circuit Range
- Symptoms-Lighting Systems
- Automatic Lamp Control Inoperative
- Backup Lamps Always On
- Backup Lamps Inoperative
- Courtesy Lamps Always On
- Courtesy Lamps Inoperative
- Daytime Running Lamps (DRL) Always On
- Daytime Running Lamps (DRL) Inoperative
- Fog Lamp Indicator Always On-Rear
- 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-Flash to Pass
- Headlamps Suggested Message On in Daylight Conditions
- Headlamps Suggested Message On in Low Light Conditions-Headlamps On
- High Beam Indicator Always On
- High Beam Indicator Inoperative
- Ignition Lock Cylinder Lamp Always On
- Ignition Lock Cylinder Lamp Inoperative
- Illuminated Entry Lamps Always On
- Illuminated Entry Lamps 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
- Park Lamps Always On
- Park Lamps Inoperative
- Reading Lamp(s) Always On
- Reading Lamp(s) Inoperative
- Rear Compartment Lamp(s) Always On
- Rear Compartment 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
- Vanity Mirror Lamp(s) Always On
- Vanity Mirror Lamp(s) Inoperative
- Repair Instructions
- Stop Lamp Switch Adjustment
- Stop Lamp Switch Replacement
- Headlamp Switch Replacement
- Interior Lamp Switch Replacement
- Hazard Warning Switch Replacement
- Instrument Panel (I/P) Dimmer Switch Replacement
- Ambient Light Sensor Replacement
- Hazard and Turn Signal Flasher Replacement
- Door Lamp Replacement
- Bulb Replacement-Ignition Cylinder Lamp
- Courtesy Lamp Replacement-Instrument Panel-Left
- Courtesy Lamp Replacement-Instrument Panel-Right
- Instrument Panel (I/P) Compartment Lamp Replacement
- Instrument Panel (I/P) Compartment Lamp Switch Replacement
- Courtesy Lamp Replacement-Rear Quarter
- Vanity Mirror Lamp Replacement
- Dome Lamp Replacement
- Headlamp Replacement
- Headlamp Bulb Replacement
- Headlamp Aiming
- Fog Lamp Replacement-Front
- Fog Lamp Bulb Replacement-Front
- Fog Lamp Replacement-Rear
- Park/Turn Signal Lamp Bulb Replacement
- High Mounted Stop Lamp Replacement
- Backup Lamp Bulb Replacement
- License Lamp Replacement (LX5 Engine/Steel Lid)
- Tail Lamp Replacement
- Tail Lamp Bulb Replacement
- Description and Operation
Factory Service Tools
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.
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