I recently bought a '99 Tiffin Allegro 28WB. There is an oval shaped light in the front under the "hood". I guess technically that wouldn't be the engine compartment. Anyway, when I first had the unit I couldn't figure out how to turn it on. Then, suddenly I noticed that it was on and now I can't figure out how to turn it off. If nothing else works, I'll put a switch on it, but it would be nice to know from whence the power comes. I looked real hard for a door switch to no avail. BTW, I found the air valves on my duallies after looking harder.