Air horn doesn't work

[Ron Baisley]

 While doing my pre-trip, before heading out to my next adventure, I found that my air horn doesn't work. I can feel the relay clicking when the button is depressed. I disconnected all of the wires and cleaned the connections, but still no air horn.                                                                                             
Ron Baisley
2005 Monterey 40'  400 Cat

[LaMonte Monnell]

Your solenoid is more than likely either sticking or has failed. If it is clicking probably sticking.

I had mine replaced a year or so ago, sometimes it would work and other times nothing.

[George H. Wall]

I agree with LaMonte, if not that blow the lines out with compressed air, as sometimes breakdown particles from the air dryer can clog the valves working parts, as happened to me.  Henry

[Gerald Farris]

Ron,
If your air pressure is up, the problem is most likely in your solenoid valve. If you have roof mounted air horns, rain water can drain down the air line and cause corrosion in the valve just like moisture in the air system. This corrosion issue can usually be repaired by spraying silicone lubricant into the valve parts and operating the valve to free it up.

Gerald

[JCMillerSr]

We also just found out that our air horns are not working.  After checking the circuit breaker and testing the wiring everything seem OK from the electrical side.  Next I removed the air line from the tanks to the horn air valve and checked air pressure.  Everything OK there as well.  I believe the horn air valve has gone bad and ordered a new one from BCS.  Hope that is all that is wrong.

PS:  Just recently we had to replace the air dryer and it is possible that during that process there was debris that could have gotten into the valve causing the problem.  Just a guess but sounds logical.

[Lee Welbanks]

If the horns are roof mounted if you don't blow them fairly often the diaphragm in the back will plug up with crap and moisture. Some of them can be taken apart by removing the screws on the diaphragm cap and clean it out.
Remove the horn from the roof and disconnect the air line and have somebody actuate the horn button and if you have air out of the tubing it is the horn diaphragm, no air look elsewhere.

[JCMillerSr]

Lee, thanks for the information.  Although I did remove and check the air line from the tanks to the horn valve I did not check either of the air lines at the horns.  My assumption, perhaps incorrect, was that if neither of the horns were working and were on separate lines the problem was most likely downstream of the T in the lines where they separate to go to each horn.  Since there was only about 6 inches of air line between the T and the valve plus there is no noise from the valve when the horn button inside is pushed the valve was obviously the most suspect cause.  New valve is on the way but in the meantime I think I will disconnect the air lines and blow them out just in case.

[Lee Welbanks]

JC,
In your case I would be looking at the valve as the cause. Let us know what happens with the new valve and post the valve number.

[JCMillerSr]

UPDATE:  Yesterday I spent some time working on the RV.  Decided to disconnect the air line from the top of the air valve and test again.  This time I heard a slight clicking sound but still no air through the valve.  Spent some time doing other things which included starting the engine and leveling the coach after pumping up the air tanks.  For some reason I decided to try the horn again and this time I heard a rush of air.  Went back outside and reconnected the air line and tested again.....the horns now work?  Go figure!  I guess the solenoid valve was stuck and finally worked it way loose with the extra air pressure from the fully filled air tanks.  I still have the new valve on order and will probably go ahead and replace it when the new one comes.  Will post later on the part number.

[Edward Buker]

JC,

You might disconnect that air line and give the valve outlet just a couple of light blasts of WD 40 and tap the horn button to activate the valve, repeat the process again. That may be enough to lube the valve and release some corrosion if that is involved. If I had corrosion X around I would use that instead.

Later Ed

[JCMillerSr]

Edward,

Thanks for the suggestion.  I will definitely take your advice and take care of this the next time I am working on the coach.