Ford Bronco Air Horn Compressor Relay Wiring Diagram - Pins 85/86/30/87, 20A Fuse

This document is a hand-drawn wiring diagram (watermarked "Adrianspeeder") showing how to wire an aftermarket air horn compressor to a standard 4-pin automotive relay, uploaded to the gallery of a 1988 Ford Bronco as "horn relay.jpg". The diagram shows the original blue horn wire from the stock relay being cut and connected to pin 85 (blue) of the new relay to act as the trigger signal. Pin 86 (green) provides the other side of the relay coil circuit, tied into the switched power line. Pin 87 (yellow) receives power from the vehicle's 12V source through a 20 amp fuse, and pin 30 (red) delivers switched power output to the compressor, which is grounded on its other terminal. From this diagram a reader can learn the correct relay pin assignments (85, 86, 30, 87), the color coding used for each wire (blue, green, red, yellow), the required fuse rating (20 amps), and the general layout for adding a relay-driven air horn compressor triggered by the factory horn circuit. The document contains no year, model, or part number information of its own.