Factory tach question

That sucks. I'm not much help, I think the 2nd connection is a blue wire from bh connector? Grey to coil -ve.
MrHeaterbox does tachs too, not cheap.
Hi Steve,
I just hooked the tach up temporarily under the hood, with wires hooked up directly 12v, negative on coil and ground.
The tach is more then likely toast
Damit.
Thanks