I read in an old thread that the roof mounted Air Horns might be Hadley's..I can't blow up the front end pic enough to read it.. Can anyone confirm the model for me so I can get info from them, unless someone has a pdf of the layout and cleaning instruction brochure..they might send to me..
http://www.hadleyadvantage.com...ions/products/horns/

Mine say Barth. You are probably right about Hadley. Mud daubers generally build a small Metropolis in things like horns, and vents. The horn button on the middle of the steering wheel operates a relay in the driver front electrical connection box. The box is accessible on my Gillig from the outside only. A worn off sticker on the door said "Not for Storage!" One of the relays in there will activate the horn, provided you have adequate air in your tanks.

Also check the plastic airlines routed to the horns.
After verifying the solenoid and valve were working and the horns were not plugged-up with insect debris, I discovered one of the plastic lines had cracked in a bend. Was accessible in the front compartment. Have someone press the steering wheel horn button while you're up in the front compartment listening. Might want to disconnect the electric horn beforehand so you don't hit your head when it goes off

see here

http://forum.aths.org/PrintTopic44109.aspx

http://www.hadleyadvantage.com...4/HADLEY_Catalog.pdf

https://www.thetruckersreport....n-horn.301765/page-8