Tach wiring

Are you sure the grey wire is really grey?

Ohm test between the orange and grey then orange and green, which ever yeild 0.000 would be ign/dash lights


Then just hook up the orange and black then the green to coil neg, it can't hurt anything that way...and if it it read with motor runing or zeros with just key on, there ya go..


I don't understand your strategy on this at all. In any case, here's what the 67 shop manual said

Black is ground

Green is coil neg

Orange is lamp

Violet is what's left, obviously goes to switched power.