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 MANUALSGMC1994C3500 HD 6.5 F, AUTOMATICREPAIR AND DIAGNOSISELECTRICALCOMPONENT LOCATIONSELECTRICAL COMPONENT LOCATORCONTROL UNITS
1994 GMC C3500 HD 6.5 F, Automatic
Control Units
1994 GMC C3500 HD 6.5 F, AutomaticSECTION Control Units
CONTROL UNITS LOCATION
| Component | Location | |
|---|---|---|
| ABS Diode Module | Under left side of dash. | |
| ABS Module | Mounted on side of brake master cylinder. | |
| Audio Alarm Module | On convenience center. | |
| Coolant Level Sensor Module | Behind center of dash. | |
| Cruise Control Module | Under left side of dash. See Figure. | |
| Daytime Running Lights (DRL) Module | Behind left side of dash, taped to panel wiring harness. | |
| Engine Control Module (ECM) (5.0L & 5.7L M/T Heavy Duty) | Behind right side of dash, near blower motor. See Figure. | |
| Glow Plug Controller (6.5L) | On left rear of intake manifold. | |
| Fuel Module | ||
| 5.7L Heavy Duty | Behind right side of dash, above blower motor. See Figure. | |
| 7.4L | Behind left side of dash, behind brake booster. | |
| Ignition Control Module | On center rear of engine, near ignition distributor. | |
| Knock Sensor Module (5.0L/5.7L M/T) | On top right of engine, on valve cover. See Figure. | |
| Powertrain Control Module (PCM) | ||
| 4.3L California | Behind right side of dash, near blower motor. See Figure. | |
| 4.3L W/4L60E A/T | Behind right side of dash, near blower motor. See Figure. | |
| 4.3L W/4L80E A/T | Behind right side of dash, near blower motor. See Figure. | |
| 4.3L M/T | Behind right side of dash, near blower motor. See Figure. | |
| 5.0L & 5.7L W/4L60E A/T | Behind right side of dash, near blower motor. See Figure. | |
| 5.7L W/4L80E A/T | Behind right side of dash, near blower motor. See Figure. | |
| 6.5L Diesel | Behind right side of dash, near blower motor. See Figure. | |
| 7.4L A/T | Behind right side of dash, near blower motor. See Figure. | |
| 7.4L M/T | Behind right side of dash, near blower motor. See Figure. | |
| Radio Receiver Module | Behind center of dash. | |
| Transmission Control Module (TCM) | Behind right side of dash. | |
| Wiper Motor Module | ||
| Front | On firewall, behind wiper motor. | |
| Rear | On lower inner center of rear window. | |
RENDER: 1.0x
NO RELATED
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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.