I tried hooking a set of console gauges like this this week and it didn't work. There's a 12 volt difference between the horn relay and the voltage regulator with the key off and it pegs the gauge. I ended up running the wires between the horn relay (like in the picture) and to the junction block hidden behind the battery. It now makes the needle run slightly to the left with the lights on and up to the first line to the right when the engine is running. I don't have a fuse in the wiring yet, but I was still figuring out a good place to hook up the wires.