Wouldn’t you want to use the air horn when the H2 is turned off? I would! The compressor should only run if needed to fill the tank. If installed correctly there should be no leaks so the compressor should not come on when the H2 is off. I would wire is to a constant source under the hood and make sure to fuse the connection. If you can’t find anything un-bolt the fuse box/relay box under the hood and access the wire you need from the bottom of it. BIG-C

White 03-H2-LUX

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