Factory sealed beam headlights on 1973–1987 Squarebody trucks are dim and outdated. The factory wiring compounds the problem — the headlight circuit runs through the switch and loses voltage before it hits the bulbs.
COMMON ISSUES
- Factory wiring drops 1–2 volts by the time it reaches the headlights
- Melted headlight switches from high-draw sealed beams running through the switch
- Corroded sockets cause dim or flickering headlights
- Sealed beam H6024 units produce poor output by modern standards
WHY YOU NEED A RELAY HARNESS
- Running LEDs without a relay harness can damage the factory headlight switch
- Relay harness bypasses the switch — direct battery power to bulbs
- Fixes the voltage drop problem and protects the wiring
- Essential for any LED or high-output halogen upgrade
LED UPGRADE OPTIONS
- 7-inch round LED sealed beam replacements are direct bolt-in
- H6024 round units are the correct size for Squarebody trucks
- Look for DOT-approved units — unapproved LEDs create road glare
- Chrome retaining rings are available if stock rings are pitted
INSTALLATION
- Relay harness installs in 1–2 hours with basic tools
- LED sealed beams are direct replacement — no wiring changes to existing sockets
- Aim headlights after install — LEDs need adjustment just like halogens
- Some LED units require an anti-flicker resistor on certain charging systems
WHAT TO AVOID
- Running LEDs without a relay harness — will destroy the factory switch
- Cheap LED sealed beams with no DOT approval — glare causes problems on-road
- Skip the halo kits if road visibility is the goal
Recommended Parts
- VCSZKXLY 7-Inch LED Headlights Round for Chevrolet C10 Pickup 1962-1980: Amazon.com
- True Mods H6054 H4 LED Headlight Wiring Relay Harness Kit: Amazon.com