I just solved a very frustrating problem with my brand new trumpet horns. At the beginning of the season they became intermittent and then failed entirely giving only a dull "thunk" sound. Normally I'm very systematic about tracking down problems (I'm an engineer by training), but for some reason I went about this totally wrong... Long story short, after a lot of chasing around I discovered that the installer spliced the ground wire from the horns in to the ground connections at the back of the switch, instead of wiring directly to a ground bus. I just extended the ground wire directly to a ground bus and voila!
Anyways a good reminder: even though it seems like hooking into the black wires at the back of the switches seems like a fine idea, don't do it. Especially for high-current devices like a horn. I guess I probably have a bad crimp or something in the ground connections behind the switches, but that path is only used for the switch illumination lamps, so I'm probably just going to ignore that for the time being.
Anyways a good reminder: even though it seems like hooking into the black wires at the back of the switches seems like a fine idea, don't do it. Especially for high-current devices like a horn. I guess I probably have a bad crimp or something in the ground connections behind the switches, but that path is only used for the switch illumination lamps, so I'm probably just going to ignore that for the time being.