Air Horn Problem

I can't figure out why my air horns don't work. I checked the solenoid, and it is working. I disconnected the lines going out of the solenoid, and got a blast of air when the horn button is depressed, but no sound.

I removed the plate from the back of the horns to see if I could feel any air when the horns are blown. I couldn't see or feel anything at that point. Should I feel anything at that point? Is there any kind of valve between the solenoid and the horns themselves that could be preventing air from reaching the horns once it leaves the solenoid?

Do you have a switch to select air horns or conventional horns?

Our coach has a selector switch and that can be a problem as can the actual horn button itself.

I'm curious what you find. My airhorn isn't functional, and it's something that's been on the list (down low in priority) to get fixed. My regular horn does work, and I've never seen any indication of a switch. I was told it's probably done by hitting and holding the horn button on drivers wheel. Doesn't work currently.

Let me know if you find anything!

Thanks,

Maybe I should have been more detailed.

On both our coaches we had a horn selector switch. If you have both regular horns and an air horn it is likely you also have a selector switch. Also check to make sure it is not something simple like a loose terminal at the horn button which we had once.

I just had my horny problem solved and it was a good feeling to have it work when I wanted it. I do not drive by the horn, but when you don't have it you miss it the most.

My horn only worked when the steering wheel was collapsed to the lowest position. when I telescoped it, it would cease to work. I pealed back the boot that covers the part that goes to the center of the steering wheel and found that was being lifted away from the steering wheel when I pulled up on the wheel when I drive. I fastened the boot differently and my horn problem is solved.

Your's may be another problem.

Lew

I am not aware of a button to switch from air to regular horns. I do know that when I press the steering wheel, my regular horn blows and the relay that goes to my air horns is energized. I removed the air line and verified that there is air leaving the air horn relay. After removing the back plates of both air horns, I could not tell if any air was arriving at the horns themselves. I couldn't hear or feel anything. If I have a button to switch from regular to air horn, it would have to be controlling a second relay at some point.

Dale
when you push the horn button do you hear any air leaks between the solidnoid and the horn? You could blow some air from the horn to the solidnoid, if it goes easy you have a disconnection or hole in the air line.
GregM

I have not chimed in on this one until now because our bus is different. Our air horns are activated by a seperate button on the floor that you step on, buy the way that we think is pretty neet and would not want to change.

If you could not tell if air was coming out with the back plates removed that is a problem for sure. The more air there the better the sound.

Also just for your information the pitch of the horns can be adjusted if they toot a bad tone by turning the "trumpet" either clockwise or counterclockwise. Often times though if they are "older" they could be difficult to turn if not froze in place. Additionally if anyone has seen those "train horns" sold in truck and chrome shops they are VERY impressive. Truly a sound worthy of a Prevo. They are very fun to use while waiting behind somone waiting for a train who gets impatient and decides to go around the gates!

I definitely could hear no air at the back side of the horns when the back plate was removed. I don't hear any air escaping from the lines when the horn button is pressed. I did get a pulse of air when I removed the line from the "out" side of the solenoid, so that makes me think there must not be a leak, but maybe a blockage. I suppose I will have to remove the horn to get to the connection on top of the bus. Maybe that will tell me something. I haven't yet removed the horns yet because the base is really sealed tightly with silicone or something similar. I just find it strange that both lines could be stopped up at the base of the horns at the same time.

I assume if I had a button to switch from air to electric horns, the control would be at the solenoid in my steering compartment, but I do know that the solenoid engages at the same time my electric horns blow.

My horn selector is a switch on the dash that looks like all the other Prevost switches.

Often times truck horns, like everthing else fail due to non-use. Rust and corosion and build up occur right at the oriface in the base of the horn itself. Their proximity up top and forward contribute to this as well. Even horns that retain the front shields are not exempt from this and if the covers were gone for any period of time or if in humid climate or not used often, any or all of these factors will cause a failure due to corosion and road crap building up and plugging the oriface in the base. I'll bet if you pull them you'll find you do in fact have air getting to them.

Electrolisis could also be a contributing factor here as well. I'm not sure what the roof is but the Pete is aluminum and even with a good gasket the hardware creates it. I've had horns plugged up before and you can bring them back with some removal and cleaning. If you do be sure to free up the threads at the base of the trumpet so you can play with the pitch when done.

We all know the old attage- check the simplist things first, and, dont forget to exercize the horns, they need it just like everything else! A great job for the kids!

Hi Dale. Can you blow air from a air compressor hose, thru the line you took off the solenoid? Or maybe get a can of Air and hook it up to the air line .
That would tell you if you have a blockage. Gary

I will try blowing air through the lines, and if that doesn't work, I will remove the horns and check them.

When you remove the back plate that exposes a thin round piece of metal that can be removed, the diaphram. You should then be able to get a better look at the oriface.

Hers a free catchy title. Someone else take it from here.