Mk2 tach input/power pins

[blackdogvan]

Can anyone tell me why some diesel tachs from the 80's qauntum / vanagon / jetta era have 3 input pins & others have 4?

[blackdogvan]

Figured it out, one lead in the foil circuit "board" does a loop. So all the tach's i've been playing with (gas / Diesel) share the same 4 pin, 3 socket on foil connection. Whew, I bet there was quite a few sleepless nights out there in vwdiesel land over this...

[RabbitJockey]

what? post a picture