well i screwed up a tach on my luv by barely reading instructions i hooked the wire that supposed to go to the coil but put on the resistor

i didnt know i just looked at the picture barely thought it was where it went boy it fried the tack it went backwards kinda funny lol so dont hook up to white resistor on top of coil and also for hooking up the light on one be careful where you connect too i blew out a couple fuses

get a test light and check they come in hand
their is only 4 wires at least on mine
I believe it is white one for ground, black to coil, green one for light at night and red for constant power
but just read the instructions if you have any
hope this helped