Horn Ground

Does the mounting bracket for the horn act as the ground?

Mick M.

Mick,

The grounding is made through the horn button which competes the circuit.

Cheers,

Rob

Thanks Rob.

robgeskey Wrote:

pretty sure the 74.5 has + wire switched as is my 76.

Mick has a 74.5 B and yes, the hot goes to the horn button but that is where the ground gets made to complete the circuit. It was wired that way until supposedly 1978 when the horns became the ground point in the circuit. I know my 74.5 is as stated and all of the wiring diagrams I have also agree with what I have stated here.

If someone has documentation that runs contrary to what I believe is correct, I would appreciate a copy of it.

Cheers,

Rob

Rob, my 76 is wired as you describe. I know, because I just put in relays, and traced the circuit carefully before I did it. So I believe you are correct - it changed in 1978.

John,

Thanks for the input. I know it changed by '78 since my V8 beast is wired the other way.

Cheers,

Rob

When I hook up the horn with double wires, the one on the left, it will sound. when I hook up the second horn I get nothing. I assume the small wire running from the first horn to the second horn is faulty. If that is the case, can I run a new wire from the connection at the first horn to the second. Or am I missing something else?

Believe it or not its still a ground issue. Ran into the same thing on both my b's. On my 75 I went with a horn relay and it solved the problem on the 73 it turned out to be a contact problem at the horn button.

Check the contacts there and if your still running the stock wheel I would highly suggest cleaning up the horn plunger and the contact between the stalk and the steering wheel hub. Also if you can pull the wheel and look at the contact point for the plunger. Odds are its pretty nasty. You can rotate the connector to get a fresh contact point. After doing this on my 73 the horns went from non existent or very wimpy to loud as heck and reliable.

Removed the steering wheel and did all the clean up as suggested. Still only the left side horn (as pictured above) would sound if hooked up alone. Hook up second horn and nothing. Decided to try a separate ground on the second horn and it worked. (Just used a wire with two gater clamps) After a successful test I removed the test ground and hit the horn push again and it works. With no separate ground. I feel good that it works but I'm not sure what I did to make it happen.

Mick M.

My 74.5 has ground wire going to the button when depressed it grounds to the slip ring thru the spring loaded button to ground on steering shaft.

If you measure voltage on the wire to the horn button you will read something less than 12 volts however since it goes thru the horns coils first with 12 volts on the horns. It will light a test light to ground. Dont be fooled and hook a radio to it. DPO did that and it drained my battery in a couple days. Dang wonder the horns didnt blow. They did click however.

Thanks folks. I'm going to clean up the installation and call it a successful mission.

Mick M.

Subtle hint - buy a relay kit!

The folks are correct - prior to '78 the horn is "ground switched" which means power (12v) is supplied to the horns at all times, then current flows by completing the circuit to ground through the horn button. This is true for both +ve and -ve ground vehicles!

For '78 and newer cars, the horns are always grounded, and power is switched to complete the circuit.

Both versions benefit from the relay, but especially the cars with a horn push in the center of the wheel - it is VERY prone to burning and arcing at the "slip ring" connection. The relay prevents this!

should be two purple wires going to rh horn and one to the lh horn. The rh horn will have one purple/black going to the lh horn. and lh horn will have two purple/black one of which goes to horn button.
Check you lh horn by putting 12 volts on one terminal and ground the other one if it doesnt blow or atleast click a little then you have a horn problem. Some of the older hors could be opened and adjusted.

Eric, what's subtle about "buy a relay kit"? LOL.
Will the one you supply work for this? If so, I'll take one. I hope you will also send instructions on how and where to install it. I'll PM you so we can get moving on this. Thanks.

Mick M.

Gil, looks like your Hooters are working just fine. Please excuse me if one of those fine looking ladies is your daughter. Congratulations if one is your wife. Please forgive me if one is not your wife but your wife reads this.

One more question. Should I not hook up my horns until I get the relay?

Hook em up I dont have a relay and they work fine. If one blows thats good if u need one.

Right after I got the '73, one of the first things I did was add a relay to the horn circuit. Didn't make any appreciable difference either way, to the ear anyway, but it was easy to do and good practice for the real deal later on: Headlights and heater fan. I don't see any reason to ever remove it, and I didn't hesitate to replace the bad one when it failed.

Both of them work now. One high tone and one low tone. I have two good hooters now. I mean tooters.

Pooty-whoot!

Sorry!

Yes, the kit will work fine - for $40 it is both a great help to the horns and lights, but it is is also easy to fit - and remove! Yes, it comes with instructions!

I sent you a PM, but I'll build a kit for you tomorrow - and it will be in the mail on Monday!