1990 Ford Bronco Alarm Relay Wiring Diagram - Dome Light Black/Blue Wire

This document is a simple hand-made wiring diagram showing how to connect a standard 5-pin automotive relay (pins 30, 85, 86, 87, and 87a) for an aftermarket alarm installation. The diagram shows the relay outline with its pin positions and the connection for each terminal: pin 87 connects to the negative alarm wire, pin 85 connects to ground, pin 30 connects to ground, and pin 86 connects to the black/blue wire found in the kick panel (the wire going to the dome light). Pin 87a is shown in the diagram (grayed out) but has no labeled connection, indicating it is unused. The diagram was uploaded to a 1990 Ford Bronco gallery, suggesting it documents how to trigger an alarm's door-input from the Bronco's dome light circuit using a relay. A reader can learn the exact relay pinout wiring needed to interface a negative-trigger alarm input with the black/blue dome light wire in the kick panel of the vehicle.