I wired my unit into the main bus . When I turn on my other GPS unit (Standard Horz.) the Helix 7 brakes up and dims. Because of the interference I was told to run the wires directly to the battery with a inline fuse. I hooked it up to the battery switch and engine ground. Now when I have my Helix7 on and start the engine it blows the fuse inline with the Helix. Does anyone know why or what I'm doing wrong?