I've found a tach in my junk pile and would like to install it on my truck. The problem is that there is no instuctions, just wires out of it. Are tach wire colours standardized? The coloured wires I have are Green, red, blue, yellow and black ( five wires only ).
Thanks.

 

All the ones I have seen use 4 wires. What brand is it?

green - ignition

white - dash lights

black - ground

red - power when key is on

 

Where on the ignition would I put the green wire?

 

The negative side of the coil.