It just stopped operating, the parts are still there, but the light does not come on, or chime. . Yeah i found out the hard way but without damage. Any ideas
I don't know how much I might be able to help since my coach is 8 years older. It seems unusual for it to fail in the "antenna down" condition. Mine has a magnetic reed switch mounted to the roof surface. It's white plastic about 2 inches long and about 3/8" wide x 3/8" tall with two wire coming out inside a split loom sleeve. The magnet looks identical (but without the wires) and is mounted on the lower of the two parallel arms. All I can think is the switch may have failed in the "make" condition - which I would think is unusual. Or the magnet fell off (mine is held with screws) and it's magnetically held to the switch creating the "antenna down" condition. I can't offer any more advice other than to dig out those schematics and multimeter and trace it down or give James Trianna a call a Foretravel. Hopefull others with more info can chime in.
Disconnecting the wires from the antenna switch should cause the alarm to come on. If it doesn't there could be a short farther up the line toward the dash. Is the alarm working properly for other functions like low oil pressure, low air pressure, turn signals, etc.? After purchase, I had to replace a bad antenna switch that was alarming all the time. Previous owner had taped over the sounder as a fix, so that I had no alarm for anything. Fortunately my wife could still hear it otherwise it may have been months before that feature was discovered. There is a volume control next to the sounder on the back of the warning light bar. I keep mine turned up to full volume so that it will really annoy me if it goes off. This refers to my 96 U270, your FT may be different.