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.
1996 GMC Forward Control 4.3 Z, AutomaticFACTORY OEM SERVICE PROCEDURE
Buzzers, Relays & Timers
BUZZERS, RELAYS & TIMERS
| Component | Component Location |
|---|---|
| A/C Enable Relay (4.3L VIN W) | Left side of engine compartment. See Figure. |
| A/C Enable Relay (5.7L VIN R) | Left side of engine compartment. See Figure. |
| A/C Enable Relay (Commercial Van) (7.4L VIN J) | Right side of driver's island. See Figure. |
| A/C Enable Relay (Motor Home) (7.4L VIN J) | Engine firewall relay bracket, under battery junction block. |
| Auxiliary Engine Coolant Fan Relay (6.5L VIN F) | Engine firewall relay bracket, under battery junction block. |
| Brake/Trans. Shift Interlock (BTSI) Relay | Mounted on top of support bracket at driver's island. |
| Daytime Running Lamps (DRL) Relay | Behind left side of dash. |
| Fan Control Relay | At main support bracket, behind steering column. |
| Fuel Pump Relay (4.3L VIN W) | Left side of engine compartment. See Figure. |
| Fuel Pump Relay (5.7L VIN R) | Left side of engine compartment. See Figure. |
| Fuel Pump Relay (7.4L VIN J) | Left side of engine compartment. See Figure. |
| Glow Plug Relay (6.5 VIN F) | At top rear of intake manifold. See Figure. |
| Hazard Lamps Flasher | Behind left side of dash, above steering column (body builder installed). |
| Horn Relay | On top of main support, at driver's island. |
| Park Brake Pump Motor Relay | On right frame rail, behind transmission. |
| Seat Belt & Headlamps Alarm | At the bottom of the dash fuse block. |
| Starter Relay (6.5L VIN F) | Engine firewall relay bracket, under battery junction block. |
| Starter Relay (Gasoline) | At relay center, on right side of driver's island support. |
| Turn Signal Flasher | On dash fuse block. |
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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