The Stovebolt Site Forums The Shop Area The Electrical Bay horn suggestions

Scott, Jon G's description is spot on. Just in case it may help you and anyone else reading this thread in the future (a picture is worth a 1000 word - lol), see your edited pic below. Red arrow = Voltage Regulator / Green arrow = Horn Relay / Blue arrow - Fuse Box
Hope this may add in the help department.

Testing if voltage is present, it's easier to just buy an ice pick volt tester. very cheap, no knobs. Just lights up, lots of uses. Nothing to drop on the floor.

Also, I keep saying...there is no ground from relay mount to chassis necessary on the horn relay. The ground wire from the horn button is ISOLATED to the relay coil. It is ground switched/triggered. Some folks may be thinking of a remote starter relay/solenoid. It's coil needs grounded by it's mount. All of it's terminals are hot and it is hot switched/triggered.

Scott, Wire your horn as we have described now that you know which thing is the relay. Follow the three wires on it first and see if where they go makes sense.
Do all this visual check and wiring with the negative battery cable DISCONNECTED from the battery post.

Sorry Scott, I called you Steve, I was dealing with a Steve somewhere and got mixed up. Very sorry.

Appreciate all the responses! You guys are great! I am waiting for the horn to arrive (ebay) and will update.

Thank you.

All that I can add is Indiana got rid of the inspection law many years ago. Neither my truck or MGA would have passed. When they did have them the MGA passed but the inspector could not fit in it. He knew so little about it he did not try to find the horn or the light switches.