Horn does not alway sound..help

I have a GG train horn wired up to the stock horn wiring on a 1993 Ford Ranger. Anytime the vehicle is started it will always honk, but when the truck is off or in accessory it is hit and miss for when it will honk. I cannot figure this out because the stock horn honked regardless of the vehicle running or not. Any ideas would help.


When you say hit or miss - that makes it sound like a bad connection.

But if the truck i started it always sounds, never fails. I am at a total loss at figuring out what is going on.

I assume the GG trainhorn is air powered - so your horn button is operating a solenoid valve?

Only thing that comes to mind is that your voltage is probably better/higher when the engine is running. Then there’s enough to overcome a bad ground/connection or a weak/sticky solenoid valve.

A way to test would be to try ‘key on’ and ‘engine off’. You should still have problems.

Either way, check your ground and connections.

Thanks for the info, I will begin troubleshooting the connections after work.