When I got my '69 the horn didn’t work at all. I replaced the dried up rim blow horn switch and it worked, but I found someone in the past had unplugged the hi horn. I plugged it back in and just got a clicking sound so I found out why they unplugged it. I left it this way for a while. I ordered a replacement hi horn from WCCC and installed it yesterday.
To my disappointment I got the same result with both horns hooked up, just a clicking sound. I messed with the screw on the new horn and got both to blow one time, then nothing again, even if I unplugged the hi and had it like before the lo wouldn’t blow anymore so needless to say I wasn’t happy and felt like I took two steps backwards
Is there anything that would be causing this? From the little bit of research and reading I’ve done it seems the horn systems on these cars weren’t that great and problematic. I’ve heard of some guys doing a relay to get full power to the horn, but I don’t know how to hook it up, maybe I could find someone that maybe have documented it.
Run a jumper wire from your battery positive to horn to make sure they work before spending money. The horns ground to the radiator support, so make sure you have good contact there too.
before I bought my new horn I took a wire wheel on a drill to the old horn’s mount, spacer plate and radiator core support. I did test the new horn with a jumper wire from positive on battery to connector on horns, they both worked this way.
I would like to make the factory setup work if possible, but will definitely keep the relay kit in mind.
Check the voltage going to the horn(s).
There is a lot of wire and multiple connectors between battery and horns.
Simplified horn circuit: Battery → headlight switch → rim blow → horns
High resistance in that circuit will result in low voltage at the horn making them non-functional. Since you ‘hot-wired’ them and they work the problem has to be in the power delivery circuit.
After mowing the lawn last night I had my girlfriend come out to help me test the voltage on the horns. At first we couldn’t get a reading no matter what so I pulled the steering wheel center cover and tried a jumper wire across the terminals, nothing. I started to move the wheel back and forth and finally started to get a reading. I had “adjusted” the horn contact springs last year so was surprised I was having problems with them making contact. If I remember right I put dielectric grease on the contact pad on the wheel so not sure if that is causing a problem with it or if there is some “trick” I don’t know about when setting the springs up and putting the wheel back on.
I tested the battery before we did the voltage test, it was 12.25 volts. During the horn test we were getting between 4 and 10 volts; the longer I had the horn on the higher the voltage reading, probably due to the fact my meter is just a cheapie from Harbor Freight and the meter maybe didn’t read full voltage right away?
I think at this point I’ve pretty much made up my mind to add a relay.
I hooked up the relay yesterday. I bought a Standard brand, wired it up and it didn’t work, the most I would get out of it was the horns would honk for a split second and then they wouldn’t do anything until I came back a couple minutes later and tried again and would get the same result. I had a couple 12v relays laying around that we pulled out of a junkyard years ago. I wired one of these up and got the horn to blow, but the relay was staying warm and the springs on the turn signal/horn switch would get red hot after a second or two of having the horns on.
I looked around on the net some more and realized I had it wired wrong so I fixed that and replaced the springs on the horn contacts with springs out of a couple click pens that I cut down to length, the horns are both working and are pretty loud, this is a great upgrade and even though the whole project was a pain from replacing the horn switch in the rim blow wheel to the bad out of the box relay I’m glad I did it!
Which Standard relay did you use? If it’s the one they advertise as a replacement horn relay it will not work for our systems. It is for early (generator) '65 Mustangs. The circuit was changed and no relay from the factory on the '66+ models.
I used Standard part # HR127. I guess in later years Ford went back to a relay in the horn systems? My buddy had a 71 Mustang and I was telling him about it, but I told him I didn’t know how long they used the same system that is in my car, do you know?
Standard lists that relay as fitting almost every ford car and truck from 58-89.
I only deal with the classic years 67-73 and a little on 65-66 Mustangs so I can’t say for sure, but I do know that I have sold a lot of P&P kits to folks with Ford cars and trucks from the mid 60s and early 70s that do not have a factory relay.
It has a 1964 Galaxy part number (C4AZ-13853). I think it was probably used on full size Fords & trucks, but don’t know for certain. It is one screwy relay, though. As built is doesn’t function like a relay and it has no alternative power source - it is more like an inline on-off switch. Very strange.
