update. problem fixed!!!!!!!!! pilot error!!!! the horns do work. just could'nt hear em above the chassis horns. makes me wonder, why did they bother? thanks to all.

My 2007 Dolpfin 5342 also has roof horns,ford Chassis] I unhooked the frt under hood horns to see if the roof ones blow,they are all hooked together, and yes they work. Hope this helps..

I had the same problem, I removed the roof horns,placed them on my work bench. removed the rear retaining screws, removed the cover. What I found when I removed the cover was 12 volt coil and aset of contacts( almost like a set of points you would find in a car distributor) I cleaned the contacts with a point file. Got my 12 volt jumper pak, with two short pieces of wire. and what do you know, they worked