1st generation tach question

[Dodgerdallas]

The wiring is a mess behind the cluster and im trying to see if the tachs operating,the wires off the sender behind the glove box are black,yellow and gray,there are 2 posts on the back of tach,which wires make the connections to them? Ive got the cluster out and im looking at them (posts) from behind,need to know what goes on left and right sides.I have a diagram but its showing more rear connections than I have and there are no wires coming from the harness behind cluster that even look familiar (mess)-any help?

[A383Wing]

short version...

wires to sender are purple, 12v....yellow, to tach, and gray, to neg side of coil, bod of sender is mounted to dash which is ground for sender.....yellow wire from sender goes to back of tachometer in dash. There is only one wire to tach, it goes on the spade terminal. Nothing goes on the other tach terminal

Note...all including the dash must be mounted or grounded in order for everything to work properly

I bet you are using a 67 wiring diagram...which won't work...complete wire harness's are different and will not interchange...I have 66 diagrams and service manuals if needed

[Dodgerdallas]

I'm sorry the wire IS purple and not black-the tach I have has 2 posts on the back,there is no spade- looking at it from the back, which side does the wire connect to ?

[A383Wing]

it will connect to the passenger side stud..should be a spade terminal on it...also should have insulator under the spade so it does not ground out on case

best pic I got right now...will look for another

[Dodgerdallas]

Ok the spade is gone off mine, as I explained the wiring is a mess- thank you for the info

[A383Wing]

another pic of a 66 tach

do you have the insulator on there? I have many of the correct spade terminals for the tachs

[Dodgerdallas]

That would be it thanks- one more question , that ground strap off speedo , does it ground to dash or?

[A383Wing]

ground strap goes under the speedo screw on the back and the "pointed" part touches the back of the cluster housing

[Dodgerdallas]

Hittin the sack,thank you so much !