so the other day my factory tach crapped out so im installing a new one, Now ive never installed a tach before but it seems simple enough (its for a 90 gt by the way). The instructions say BLACK to negative cable/ground, RED to any wire energized when ignition is on run (i can use my fuse box right?) WHITE to any instrument lighting panel circuit controlled by instrument panel dimmer control (so can i use the headlight wire or any wire on the dimmer switch?) and the GREEN to the negative side of coil (there are two wires into the coil but im not sure which is the negative. I tried to search but there are to many different answers and wires people used. Im trying to hook it up before dark so any quick help would be awesome