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 Chevrolet Chevy Express H2500FACTORY OEM SERVICE PROCEDURE
Control Units
CONTROL UNITS LOCATION
| Component | Location |
|---|---|
| Auxiliary HVAC Control Processor | Behind auxiliary HVAC controller, in headliner. |
| Body Control Module | Behind lower right side of dash. |
| Central Sequential Fuel Injection (4.3L VIN X) | On bottom of intake manifold. See Figure . |
| Cruise Control Module | Near brake fluid reservoir. |
| Electronic Brake Control Module | On left frame rail, near center of vehicle. |
| Fuel Injector Control Module (CNG) | On left side of radiator support. |
| Ignition Control Module (4.3L VIN X) | On top right side of engine, at ignition coil. See Figure . |
| Inflatable Restraint Sensing & Diagnostic Module | Under left front seat. See Figure . |
| Powertrain Control Module | In engine compartment, on left inner fender. See Figure . |
| Remote Control Door Lock Receiver | Behind upper left center of dash. See Figure . |
| Turn Signal/Hazard Flasher Module | Behind left center of dash. See Figure . |
| Vehicle Communication Interface Module | Below steering column. See Figure . |
Factory Service Tools
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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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