The Stovebolt Site Forums The Shop Area The Electrical Bay Horn Relay Wiring

I finally gave up on the old 6-volt horn and bought a new 12-volt dual horn setup. I had fried either the horn or the relay or both. The new one came with no wiring instructions. It is equipped with a relay, but the terminals on the relay are not marked. At the risk of having the same thing happen as happened with the old horn, I want to make sure this time it is wired correctly. The relay is attached to the horn bracket and one terminal has two red wires, one from each horn, attached to it already. This is one of the two outside terminals. I presume these are hot leads from the horns. I am guessing that the hot wire from the ammeter + terminal goes to this same terminal on the relay. Correct? Then there is the wire running from the horn to the relay. Which terminal would this go to? Center terminal or other outside terminal? And last would be the horn button wire that goes to the relay. Center terminal or outside terminal? Last question has to do with a ground. Is one not required? Thanks.

Rick,

Have you looked very closely at the terminals, and even the bottom of the relay? Having no marks indicating what is what would be nuts.

My post will probably confuse you more. A standard horn relay would have three terminals, just like yours. The new horns you have are wired together to a terminal that is one side of a normally open contact inside the relay.

Another terminal would be power from the ammeter (or where ever) that would attach to a different terminal...this is the other side of the normally open contact that the red horn wires are hooked to.

The third terminal connects to the wire that comes down the column from the horn button on the steering wheel.

The coil inside the relay is already jumpered to pick power off the powered terminal. That third wire going up to the horn button grounds the relay coil, closes the contact and allows power from terminal two to pass through to terminal three which is attached by the red wires to the horns.

This is a guessing game. I would guess that the ammeter connects to the middle terminal and that the wire from horn button to relay attaches to the terminal farthest away from the tab with the red horn wires attached.

Three terminals....three wires. One already to the horns. One from power and one to the horn button.

The horn/relay assembly attaches to the truck somehow and that attachment is probably the ground itself.

Stuart

Correct-- middle terminal is batt, other 2 make no difference how you hook up. The horns are only looking for a ground thru the horn button

sbafarm,

It sure seems to me that each terminal would be real specific. If the middle terminal is truly BATT then there should be only one other that is coil ground, and only one other that is the NO contact.

The relay coil is what is looking for ground through the horn button...the horn is looking for power through the NO contacts. Supplying a ground to the coil closes the NO contacts and powers the horn.

Stuart

I stand corrected-- You're right. I went home and looked at the old relay I have. A three terminal style. If you look at it with the mounting on your left, top terminal is swithc(horn button), middle terminal is BATT, and bottom is horn. I even took the cover off to make sure.