Almost got my horn working. Almost.

[ncbird]

jumpers

Well not to argue with Dave but jumpers are a very usefull method of troubleshooting. If the jumper wire is of equal or larger wire gauge then there should not be a problem. In this case we already know from the original post that the horns work. I would still do one test which is to jumper from a 12v source (either the spade on the relay or the battery to the wire on the relay that goes to the horns. This in essence eliminates the relay. If they do not work with 12v on that wire we know at least one issue is in that portion of the circuit. The other thing to do is put a multi meter on the spade for the horns and see if you get 12v on it when the relay picks. The other would be to rig a temporary wire from the horn spade to the horn and see if they work. I fully believe in bench testing and have my own regulated DC power supply on my bench but I also believe in fault isolation. I bow to Dave on the information he provides and no way question his technique.

[simplyconnected]

If the jumper wire is of equal or larger wire gauge then there should not be a problem...

Grant, that scares me. From what I can glean from Dakota, he doesn't know which terminal is what. He very easily may have jumpered hot to the horn button terminal and he may have cooked his spring.

Hmm... well... I never put the full juice of the battery through to the horn button (as far as I know).

...With everything hooked up, I can press the horn button and the relay clicks each time; but the horns wont honk. Not even a chirp.

If I reverse the two wires (not the horn button wire), then the relay will NOT click when I press the horn button.

...So, which relay terminal is which? (I assume all wires are disconnected and the relay is on your bench.)...

Grant has the right idea of using a bench power supply, Dakota. It can be a 12-volt car battery.

Pull the relay out and test it on a bench. Doing this will make SURE you don't damage your skinny wires (and spring) going from the relay to your horn button. The fuse will NOT blow before damage is done to your column circuit. That's why Ford used a horn relay. Only miliamps are used to turn the relay on. Relay contacts pass power to blow the horns. NONE of that current goes through your steering column.

Follow my instructions and verify your relay is good or bad. Use a small load like the test light I described.

After you know what terminals are what, and have identified the wires, you can mount and use all the jumpers you wish. Never assume terminal positions, and use all your senses. - Dave

[ncbird]

amen

we are in total agreement Dave

[scumdog]

On this subject: Do '66 T-birds have horn relays?

I have not run across one and have a feeling the whole horn current goes through the steering whell contact.

I know my horns do not work/work well until the motor is running (and the battery is getting some current from the alternator I suspect).

Oh, and the battery is a fairly new one and holds a good charge.

[simplyconnected]

Tom, I never heard of a car that doesn't use a horn relay. All that horn noise comes from using about ten amps; 120-watts or more. Since the horns and battery are neighbors, no sense in running heavy wires inside the car and back again, so they use a relay contact to deliver horn power, and one skinny wire to run the relay coil.

Modern cars use relays for halogen headlights for the same reason. A headlight switch doesn't need to carry huge current and neither does the 'start' switch.

Relays have been used for power windows, seats, rear window defrosters, convertible top pumps, retractable roof control, burgular alarms, A/C clutches, remote start, etc... I use one on my brake lights, so the pedal switch can be tiny (the size of a mouse switch). I also use three for my trailer lights (left & right stop/signals, and tail lights), that way the flasher rate isn't affected and no extra current goes through my steering column wiring.

Relays are **** near bullet proof and they usually last a long time; fifty years is not unusual. - Dave

[scumdog]

Thanks dave, I'll do a bit of 'investigating'!!

My car was bought from a Mexican guy who was not overly informative except to say it was "ees good car" and "just needs leetle run on freeway" etc.
However thing like the starting inhibitor had been by-passed, the drivers window motor was totally stuffed despite being told "ah, eet maybe need fixed a leetle, it works sometimess" - well, you get the picture!

So Lord knows how the horn may have been messed with!

PS: Not bagging the previous owner 'cos he's a Mex! - and maybe it WASN'T him that did the above 'fixes' anyway.

[Dakota Boy]

Update:

Horn works now.

"H" spade runs to horns.
"W" spade runs to steering wheel horn button.
Larger blue wire is the "+" from the battery.

Wire to the horns will be replaced with heavier 10-gauge this weekend.




Thanks to everyone for putting up with an electrically-ignorant noob such as myself.

[simplyconnected]

...Never assume terminal positions, ...

I had a feeling your horn button wasn't the middle terminal. Glad you got it going. - Dave

Edit: BTW, I wouldn't use wire any bigger than #14 stranded copper. In fact #16 would be ok. The reason being, how long do you blow your horn for? Five seconds? Ten at the very most? Duty Cycle plays a big role here.

[Dakota Boy]

Well, the 16-gauge wire going to the horns got pretty warm at the relay spade, and that freaked me out.

But then I was hammering the horns quite a bit there. The neighbors probably wondered what in the heck was going in my garage.