HORN doesn't always work with engine off?

[Kingfish 11]

I was running my 69 Mach yesterday and noticed something I wasn't aware of or maybe it's something that just started happening. The horn works fine with the engine running. But when I turn it off and try it I'll get a couple of good toots and then all I'll hear is a very faint sound coming from the horns.

 

I had a Corso Feroce wheel installed sometime back and I don't remember if this was happening at first.

 

Any thoughts? Thanks, Kingfish (Steve)

[69RavenConv 286]

Just a guess, but it could be voltage related. When the engine is running, your alternator puts out 13-14 volts. When it's off, your battery puts out 12-12.5. The difference might be enough to account for your situation. Horns tend to corrode inside and freeze up when they're not used for a long time. Yours might get better if you exercise them regularly or some guys will even rap them with a rubber mallet to free them up.

[Midlife 814]

There's also a small screw that adjusts the diaphragm in each horn; you can fiddle with that to maximize volume. Best to do this on Sunday mornings circa 4AM.

[J's69Mach1 17]

On my 69 , the horn was very faint and some times none. . Not enough voltage to run horns. A usual problem with our cars. Our cars came with No Horn Relays. At least for 69. i think, not sure 70 came with factory horn relay. So i added a horn relay , to keep up with horns. Problem solved in my case. Horn relay supplies plenty of juice now.

[Midlife 814]

70 did not have a horn relay, nor did 71-73's.