Frequently Asked Questions About GMC General Truck Lights
What model years do these lights fit, and are they compatible with both single and dual headlight GMC General models?
These lights are designed to fit GMC General trucks from 1977 to 1996. Most aftermarket options are compatible with both single rectangular (1977-1980) and dual rectangular (1981-1996) headlight configurations. However, always verify your specific model year and headlight style before ordering. Check your VIN or measure your existing light housing dimensions to ensure proper fitment, as some trim levels may have unique requirements.
Are these lights DOT approved, and what's the difference between SAE and DOT markings?
Quality replacement lights for GMC General trucks should carry both DOT (Department of Transportation) and SAE (Society of Automotive Engineers) certifications. DOT approval means the lights meet federal safety standards for on-road use, while SAE certification indicates they meet industry engineering standards. Look for lights with these markings stamped on the lens or housing. Avoid unmarked lights, as they may not pass inspection and could result in tickets or safety issues.
How difficult is the installation, and what tools or modifications are required?
Most direct replacement lights install using existing mounting points and wiring harnesses, typically requiring 30-60 minutes per side with basic hand tools. You'll need screwdrivers, socket wrenches (usually 10mm and 13mm), and possibly wire crimpers for older trucks with corroded connectors. Some LED upgrades may require load resistors or flasher relay replacements to prevent hyper-flashing. No drilling or cutting is usually necessary for DOT-compliant replacement lights designed specifically for GMC General trucks.
What's the difference between OEM-style sealed beam and LED conversion options?
OEM-style sealed beam lights maintain the original appearance and use standard H4 or H6054 bulbs, costing less upfront but requiring periodic bulb replacement. LED conversions offer 50,000+ hour lifespan, brighter output (typically 3,000-6,000 lumens), and lower power consumption, but cost more initially. LED units also run cooler and often include better beam patterns. Consider your usage patterns: daily drivers benefit more from LED longevity, while show trucks might prefer authentic sealed beam appearance.
Why do my new lights have moisture inside, and how can I prevent water intrusion?
Moisture buildup is often caused by damaged gaskets, improper installation, or lower-quality housings without proper venting. When installing, ensure all rubber gaskets are seated correctly and apply dielectric grease to electrical connections. Check that drain holes (if present) aren't blocked. For chronic moisture issues, apply a thin bead of clear silicone sealant around the lens perimeter, but avoid sealing drain holes. Quality lights include breather vents that allow pressure equalization while keeping water out.
