I'm trying to hook up my tach, and I've got everything hooked up except the power. I thought I had it all figured out but then I went to start my truck, and it wouldn't. So I cut that connection (which was tapped into radio power) and it started right up. So I did a search and found out that i should tap into the fuse box, with one of those plastic connectors, but where do you get those? Anyone got a part #? Help!!!