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
Electrical Component Locator: Connectors
CONNECTORS LOCATION
| Component | Location |
|---|---|
| C100 (Black, 16 Pin) | Below underhood fuse block. |
| C101 (Black, 10 Pin) | Below underhood fuse block. |
| C102 (Black, 12 Pin) | On rear side of underhood fuse block. |
| C103 (Black, 14 Pin) | Attached to front side of underhood fuse block. |
| C104 (Black, 12 Pin) | Near underhood fuse block. |
| C105 (Black, 1 Pin) | Near wheelwell. |
| C106 (Blue, 12 Pin) | Under underhood fuse block. |
| C115 (Black, 2 Pin) | At top left rear of engine, in engine harness. See Figure . |
| C148 (Light Gray, 8 Pin) | In engine harness to odd ignition coil harness. |
| C158 (Light Gray, 8 Pin) | In engine harness to odd ignition coil harness. |
| C175 (Gray, 20 Pin) | At right side of automatic transmission. |
| C200 (Black, 16 Pin) | Behind left side of dash. |
| C201 (Yellow, 4 Pin) | On left side of dash, behind left kick panel. |
| C202 (Black, 52 Pin) | Attached to transfer case shift control bracket. |
| C203 (Yellow, 2 Pin) | Below steering column. |
| C210 (Black, 12 Pin) | At bottom left side of dash. |
| C298 (Light Gray, 22 Pin) | Behind right kick panel. |
| C310 (Black, 17 Pin) | At left side "B" pillar. |
| C320 (Black, 6 Pin) | Under left rear seat. |
| C325 (Black, 16 Pin) | Under driver's seat. |
| C326 (Light Gray, 13 Pin) | In driver's seat harness, under driver's seat. |
| C327 (Light Blue, 24 Pin) | In driver's seat harness, under driver's seat. |
| C328 (Natural, 10 Pin) | In driver's seat harness, under driver's seat. |
| C329 (Natural, 6 Pin) | In driver's seat harness, under driver's seat. |
| C330 (Gray, 6 Pin) | In driver's seat harness, under driver's seat. |
| C333 (Black, 8 Pin) | In driver's seat harness, under driver's seat. |
| C350 (Light Gray, 22 Pin) | Under front floor upper console. |
| C355 (Black, 8 Pin) | At front of audio amplifier. |
| C375 (Black, 16 Pin) | Under passenger seat. |
| C376 (Black, 6 Pin) | Under passenger seat. |
| C377 (Gray, 6 Pin) | Under passenger seat. |
| C378 (Black, 4 Pin) | Under passenger seat. |
| C380 (Black, 6 Pin) | Under right rear seat. |
| C390 (Black, 17 Pin) | At right side "B" pillar. |
| C420 (Gray, 12 Pin) | At top left area of liftgate. |
| C450 (Black, 2 Pin) | At rear underside of vehicle, attached to air suspension assembly. |
| C451 (Black, 16 Pin) | At rear underside of vehicle, attached to air suspension assembly. |
| C900 (Black, 12 Pin) | Inside top left body opening of liftgate. |
Factory Service Tools
Use the Manual With the Right Hardware
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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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