Frequently Asked Questions About GMC General Truck Cab Lights

What year models of GMC General trucks are these cab lights compatible with?

Most aftermarket cab lights for GMC General trucks are designed to fit models from 1973 through 1991. However, compatibility can vary by manufacturer and specific light style. The 1973-1987 models typically have a flatter roof profile, while 1988-1991 models may have slight curvature differences. Always verify the specific year range listed for each product, as some lights are universal while others are year-specific. If your truck has been modified with a custom visor or aftermarket roof accessories, you may need to take additional measurements.

Do I need to drill holes in my truck's roof to install these cab lights?

Yes, most GMC General cab lights require drilling into the roof for proper installation. Typically, you'll need to drill five holes (one for each light) plus additional smaller holes for mounting screws. Some kits include templates to ensure proper spacing and alignment. If you're uncomfortable drilling into your roof, professional installation is recommended to prevent water leaks. A few manufacturers offer adhesive-mount options, but these are generally less durable and not recommended for highway speeds or harsh weather conditions.

What's the difference between LED and incandescent cab lights for my GMC General?

LED cab lights offer several advantages over traditional incandescent bulbs: they last 50,000+ hours compared to 1,000-2,000 hours for incandescent, draw less power from your electrical system, and provide brighter, more consistent illumination. LED lights also generate less heat and are more resistant to vibration. However, LED options typically cost 2-3 times more upfront. Incandescent lights are cheaper initially and easier to replace individual bulbs, but you'll spend more on replacements over time. Both styles are available in amber or clear lenses to match your preference.

Are these cab lights DOT approved and street legal?

Most quality cab lights sold for GMC General trucks are DOT approved and meet FMVSS 108 standards for clearance and identification lamps. Look for lights that specifically state DOT compliance in their specifications. Generally, amber lights are required for vehicles over 80 inches wide, while narrower vehicles can use either amber or clear. Some states have specific regulations about cab light colors and placement, so check your local laws. Avoid extremely bright or strobe-style lights for street use, as these may not be legal in all jurisdictions.

What wiring modifications are needed to install cab lights on my GMC General?

Installing cab lights typically requires running new wiring from your truck's electrical system to the roof. Most kits include the necessary wiring harness, but you'll need to connect to a switched 12V power source, usually tied to your parking lights or a dedicated switch. The installation involves routing wires through the headliner, which may require removing the dome light and sun visors. Each light needs proper grounding to the cab. Many installers recommend using a relay for LED lights to prevent electrical issues. Budget 2-4 hours for a complete DIY installation, depending on your experience level.