Tach with 5 wires???

Can someone tell me how to wire an old (I think SUN, no name or numbers anywhere inside or out) tach? It has a red, a white, a blue, a yellow, and a black. I hooked up the red to 12 volts, the black to ground, and the green to the distributor side of the coil. did not work. I can't find anything on it on the internet. Please help!

 

A picture would help. At a guess, blue is for the light.

 

If it's an old tach it probably needs the transformer or whatever the other part was called that came with them.

 

I had an older tach not long ago(not a sun) that had 5 wires. The usual 3 went to +, coil,and ground. The remaining 2 went to light and ground for the light. I had to remove the unit from the cup to figure out what went where. Perty easy after that. Normal Norman

 

Nailed it. This stuff called technology did away with that extra stuff.

You would be better off buying a new retro sweep tach or whatever it is.