Join Date: Mar 2002
Location: Austin, TX, USA
I think there is also a relay 101 somewhere (in the electrical stickies perhaps). If you're new to relays, knowing how one works may help you. In summary a relay is a coil of wire that creates a magnetic field to operate a switch. The coil requires only a few hundred milliamps to operate, but the switch can handle 10s of amps.
In a horn relay setup, the relay coil gets it's power from the relay bus-bar. The horn button provides a ground for the relay coil. When you press the button, the coil is energized and closes the switch inside the relay to operate the horns. So if the horn button wire was grounded somewhere or if the relay switch contacts were stuck closed it would cause your horn to sound all the time. A wiring problem at the horn relay could also do it.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI