My factory tach has proven to be highly inaccurate. I have an automatic, but I still want to have a better idea of where my shift points are actually hitting... so, I'm installing a small digital Nordskog tachometer on the A-pillar.

I'm having a problem figuring out where to "hook up" one of the wires...

Red wire: Switched 12V... Got it.
Black wire: Engine Ground... Got it.
Purple wire: Switched Headlight circuit... Got it.

Green wire: Negative terminal on coil... DON'T GOT IT

Where do I hook up this green wire? I've looked at the wiring diagram in the Chilton manual and I think I'm supposed to hook up to the white/black wire at the coil, but I don't want to fry my gauge by hooking it up wrong. Is this the correct wire?

Any suggestions?

Thanks

 

Ttt...

 

Somebody has to be able to offer some insight or point me in the right direction. Thanks.

 

I can think of three possible places-
1. The white wire on the coil that goes to your factory tach.
2. The white wire on the PCM for tach output. Pin A13(the red plug)
3. The white wire on the back of the cluster for the tach signal.(don't know which pin)

Regardless of where you hook it, you are looking for a white wire.

 

Thanks Bingo. I was thinking that I had the right wire, but I couldn't find anything/anyone to verify. I've already run the wiring up to where the coil is, so that's where I'll tap. The wire is white with a black tracer.

Thank you.