really feel like an idiot on this one. dot officer gave me hard time the other day because my top of cab air horns didn't work, and i dropped the headliner yesterday to take a look. the air valve that you pull on was bad, so i replaced it. tried it, and now the air was moving through the lines to the horns themselves, but not making any sound. the air was just coming out the end of the horns. went to wrecking yard, pulled one and put it on top of the cab and tried it. same thing, air just coming out of the end of the horn. decided to eat the twenty dollars and just go get a new one. got brand new, put it up there and tried it, same thing. the air is just coming out the end of the horn without making any sound.

 

sounds like a supply problem.. air is coming out.. but not enough to make them work..

That's my guess! Check the lines while someone else pulls the lanyard and listen for leaks

 

connect shop air at the 'supply', 'sup' or 'inlet' port of the valve, then try it... if it works then your supply is bad. the valve is supplied by a pressure protection valve - it could be bad. if the horn still sounds the same, the horn valve is the problem.

 

Might need to replace the rubber diaphram in the horn.

 

thanks a lot, horn works off shop compressor. guess i'm gonna get to tear down my headliner again. yay.

 

thanks a lot, horn works off shop compressor. guess i'm gonna get to tear down my headliner again. yay.