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 378 (LIGHTING SYSTEMS)REPAIR INSTRUCTIONSHEADLAMP AIMINGHEADLAMP AIMING PROCEDURE
1999 GMC Forward Control 5.7 R, Automatic
Headlamp Aiming Procedure
1999 GMC Forward Control 5.7 R, AutomaticSECTION Headlamp Aiming Procedure
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- Open the hood.
- Measure from the floor to the center of the headlamp bulb. (Some headlamps have an aim dot marked on the headlamp lens).
- At the screen, measure from the floor and place the horizontal tape at the measured distance.
- Measure from the reference line on the floor to the left headlamp bulb centerline.
- At the screen, measure from the reference line and place the vertical tape at the measured distance.
- Measure from the reference line on the floor to the right headlamp bulb centerline.
- At the screen, measure from the reference line and place the vertical tape at the measured distance.
Important: DO NOT cover the headlamp, this may cause excessive heat build up.
- Turn on the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.
- Adjust the horizontal aim screw (1) and vertical aim screw (4) of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
- Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
- Turn the headlamps OFF.
- Close the hood.
RENDER: 1.0x
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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.