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.
1999 GMC Forward Control 5.7 R, AutomaticFACTORY OEM SERVICE PROCEDURE
Component Locations 7.4L (VIN J) "G" Series
COMPONENT LOCATIONS 7.4L (VIN J) "G" SERIES
| Component | Location | |
|---|---|---|
| A/C Compressor Clutch Relay | In Underhood Fuse/Relay Block | |
| A/C High Pressure Cut-Off Switch | On Rear Of A/C Compressor | |
| A/C Low Pressure Cut-Off Switch | In Low Pressure Refrigerant Line | |
| Camshaft Position (CMP) Sensor | Part Of Distributor, Rear Top Of Engine | |
| Crankshaft Position (CKP) Sensor | Lower Front Of Engine, Near Crankshaft | |
| Cruise Control Module | Front Of Engine Compartment, Near Left Fender | |
| Data Link Connector (DLC) | Under Left Side Of Instrument Panel | |
| EGR Valve | Right Side Of Engine | |
| Engine Coolant Temperature (ECT) Sensor | Top Front Of Engine | |
| Engine Oil Pressure Gauge Sensor | Top Rear Of Engine | |
| EVAP Canister Purge Solenoid | Right Side Of Engine | |
| EVAP Canister Vent Solenoid | Right Side Of Engine | |
| Fuel Pump Relay | In Underhood Fuse/Relay Block | |
| Fuel Tank Pressure Sensor | In Fuel Tank | |
| Heated Oxygen Sensors (HO2S) | ||
| Bank 1, Sensor 1 | In Exhaust Pipe, In Front Of Catalytic Converter | |
| Bank 1, Sensor 3 | In Exhaust Pipe, In Back Of Catalytic Converter | |
| Bank 2, Sensor 1 | In Exhaust Pipe, In Front Of Catalytic Converter | |
| Bank 2, Sensor 2 | In Exhaust Pipe, In Back Of Catalytic Converter | |
| Idle Air Control (IAC) Valve | Top Left Side Of Engine | |
| Ignition Coil | Top Right Of Engine | |
| Ignition Control Module | Top Right Side Of Engine | |
| Intake Air Temperature (IAT) Sensor | Part Of Air Intake Duct, Front Top Of Engine | |
| Knock Sensor | Left Side Of Engine & Right Side Of Engine | |
| Manifold Absolute Pressure (MAP) Sensor | Top Right Side Of Engine | |
| Mass Airflow (MAF) Sensor | Part Of Air Intake Duct | |
| Secondary Air Injection Reaction Pump Relay | In Underhood Fuse/Relay Block | |
| Throttle Position (TP) Sensor | Right Top Of Engine | |
| Underhood Fuse/Relay Block | In Engine Compartment, On Left Fender | |
| Vehicle Control Module (VCM) | In Engine Compartment, On Left Fender | |
| Vehicle Speed Sensor | Left Side Of Transmission | |
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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