Ford Bronco Headlight Relay Wiring Diagram - Low/High Beam Relay Upgrade Schematic

This document is a hand-drawn (CAD-style) headlight relay wiring schematic uploaded to a 1988 Ford Bronco gallery. It shows how to wire two relays — a LowBeamRelay and a HighBeamRelay — to power the headlamps directly from a constant 12V battery source rather than through the stock switch. Battery power (Constant12V) feeds two 10-amp fuses; each fuse supplies relay pin 30 (Red wire). Each relay's pin 87 (Yellow) output goes to the headlamp filaments (drawn as coils, two filaments per side, grounded at the chassis). The relay coils are triggered on pin 85 (Blue), with pin 86 (Green) routed to the switches: the LowBeamRelay is controlled by the StockHeadLightSwitch, and the HighBeamRelay is controlled by a HighBeamToggle switch. Wire colors are labeled at every relay pin (30 Red, 85 Blue, 86 Green, 87 Yellow). The diagram gives no year, model, part numbers, or engine applicability — it is a generic relay-conversion schematic commonly used to upgrade headlight brightness and reduce load on the factory headlight switch. A reader can learn the fuse ratings (10A each), the relay pinout wiring colors, and how the stock switch and an added toggle trigger the low- and high-beam relays.