Color engine bay wiring diagram for an 84
 

Does anyone here have a color wiring diagram they can post here, for the engine bay on an 84 GMC?
I'm trying to hook up an aftermarket tach, but I'm not getting anything. I grounded it to the dash, connected the red wire to the only "IGN" terminal I can see, and plugged the green wire into the "TACH" port on the distributor cap. I found out the white wire coming out of the TACH port went to the plug for my ac.
Thanks in advance

Re: Color engine bay wiring diagram for an 84
 

I've only seen B&W - http://forum.73-87chevytrucks.com/sm...?topic=11766.0

Re: Color engine bay wiring diagram for an 84
 

Thanks Rocknrod. That's all I've ever seen too.

Re: Color engine bay wiring diagram for an 84
 

This may or may not help.

https://www.youtube.com/watch?v=DjpV2xvA-b4

Re: Color engine bay wiring diagram for an 84
 

GM is big on color coding, violet for starter , pink for ignition, etc, looks like you have an HEI distributor...check another GM vehicle for the tach signal color code and you will probably have your answer...most all the aftermarket wiring harnesses are GM color coded...if my memory is correct, it’s a white wire

Re: Color engine bay wiring diagram for an 84
 

Tach is white but if it doesn't already go from the distributor to the firewall you'll have to run one. My harness didn't have a white wire in it.