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 MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 61 (ELECTRICAL COMPONENT LOCATOR)BUZZERS, RELAYS & TIMERS
1999 GMC Forward Control 5.7 R, Automatic
Buzzers, Relays & Timers
1999 GMC Forward Control 5.7 R, AutomaticSECTION Buzzers, Relays & Timers
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
BUZZERS, RELAYS & TIMERS LOCATION
| Component | Location |
|---|---|
| A/C CLU Relay | In underhood fuse block. |
| COOL FAN Relay | In underhood fuse block. |
| COOL FAN 1 Relay | In underhood fuse block. |
| COOL FAN 2 Relay | In underhood fuse block. |
| FOG LAMP Relay | In underhood fuse block. |
| FUEL PUMP Relay | In underhood fuse block. |
| HORN Relay | In underhood fuse block. |
| IGN MAIN Relay | In underhood fuse block. |
| Lumbar Horizontal Adjuster Relay | Below driver's seat. |
| Rear Compartment Lid Release Relay | Below left side of dash, mounted on BCM mounting bracket. See Figure . |
| Rear Window Defogger Relay | Behind glove box, mounted to underside of cross-car beam. See Figure . |
| Retained Accessory Power (RAP) Relay | Behind glove box, mounted to underside of cross-car beam. See Figure . |
| Seat Lumbar Vertical Adjuster Relay | Below driver's seat. |
| Secondary Air Injection (AIR) Pump Relay (W/ LEV) | On left front frame rail, rear of bumper support. |
| Theft Deterrent Relay | Behind left side of dash, mounted on BCM mounting bracket. See Figure . |
| Turn Signal/Hazard Flasher Module | Below left side of dash, mounted on multi-purpose bracket near BCM. See Figure . |
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.