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.
2005 Hummer H2 V8-6.0LFACTORY OEM SERVICE PROCEDURE
Relay Box
Service and Repair
Diagrams- Relay Block - I/P C1
- Relay Block - I/P C3
- Relay Block - I/P C4
- Relay Block - I/P C7 (Trailer Wiring)
- Relay Block - I/P C7 (With RPO Code USB/USC/UNR)
- Relay Block - I/P C10
- Junction Block - Rear Lamps - C1
- Junction Block - Rear Lamps - C2
- Junction Block - Rear Lamps - C3
- Junction Block - I/P C2
- Junction Block - I/P C4
- Junction Block - I/P C5
- Junction Block - I/P C6
- Junction Block - I/P C7
- Junction Block - I/P C8
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.