So here I have an 86 cluster without tach from the truck compared to an 82 cluster with tach. The yellow circle is one difference, I don't know what that 3-prong plug does. And in red, I assume this would be the wire I attach from the coil ground side? Could I just run that wire to the screw that the pin runs to? And that switch on the back of the 86, anyone know what that is all about?
https://imgur.com/q0yrXPL
Bookmarks