So, I found a tach to replace the clock in my 85 245, it came from a 86 240, found after only 3 trips to the junkyard. My question is: if the red & white wire attaches to the +12 plug on the back, what are the +58, +32(?), -32 plugs on the upper part of the tach for? They're in a U shape, with the 58 on the left upper, +32 flat middle and -32 on right upper parts. I have plugged the tach in, and it works fine, so I know it's not related to that, but, then, what did the go to originally?

might help

http://www.davebarton.com/240tachinstall/

That is were the harness for the small 52 mm clock plugs in. Dan

Lol, thanks.