Vintage Cars: Horn TR6, triumph tr6, art allen

Question
QUESTION: Where do you connect the wires when installing a horn on a '74 Triumph TR6?

Art

ANSWER: I don't know those details for that TR, but I think it only has one horn, and the basics are reasonably obvious. I assume that the car has a horn at the moment and that you're replacing it, perhaps with a pair. The info I have has no horn relay in the circuit, and I doubt you want to rewire the horn button on the steering column unless that has failed. (Check with a 12V test light: the wire must go live when the horn button is pressed.) If OK, you can certainly use the current horn wire, at the horn. When you break the wire, make sure that your new connector (inline bullet is good) is either really well crimped or (better) put a dollop of hot solder in the crimp. Horns actually take a lot of amps!

If my assumptions are wrong (e.g. your car has no horn at all at present, or it's not working), re-post with more detail.

JJ

---------- FOLLOW-UP ----------

QUESTION: THANK YOU for your quick response! The TR6 has a horn with a red wire and a black wire. Both ends of the red wire are still connected. The black wire is connected at the horn but the other end is dangleing loose. I can't locate where to connect the loose end of the black wire.

Art Allen

Answer
Followup...

First..as the owner of an ancient car (!), you really need either a 12V test light or a cheap voltmeter.

You need to disconnect both wires and then find out which goes live when you (or helper) presses the horn button (ignition on). If neither does, then suspect the horn button on the steering column. If one goes live, connect that wire to the horn, and it should make a noise, assuming the horn is grounded to the frame. If that works, forget the other one! If it doesn't work, make sure to loosen the screws mounting the horn to the bodywork, grind a bit, and retighten, to make sure that the ground return is good. Then try again.

However, as you are gathering, I have no idea why it has two wires: usually the live input (rom the horn button) would be sufficient, with the horn grounded to make the circuit. Sorry not to be more expert, but I hope it won't take you long. All the horn needs is 12V, supplied when you push the horn button.

(Is it possible that a previous owner had a pair of horns? In which case the second wire is live and goes off to a second horn?)

If the horn is dead, obviously the noise test won't work. If you can definitely get 12V across the horn teminals (check using light or voltmeter--just hold the wire on the horn terminal with your finger) and it doesn't make a noise, then you have a dead horn.

And of course it's possible (given my ignorance) that the TR horn needs a complete circuit, rather than just a single live input and ground for the return. In which case, mea culpa. (Any real TR experts out there?)

JJ

PS If the horn is not grounded (i.e. both terminals are needed), then the black wire should probably go to a suitable ground nearby. But I don't have a wiring diagram. You might be able to find one via Google. Much the easiest would be just to try it: make red live (e.g. temporary to the battery) and black to a nearby bodywork screw: you won't wreck anything, and probably not even blow a fuse. If the black comes off the same terminal as the red (i.e. there's zero resistance from red to black), it's probably for a second horn. That's as far as I can take you without a wiring diagram.