help i have a vdo electrical tacho, & i am a little confused how to wire it up. it is an 80mm dia gauge looking at the back side of the unit there are four spade connectors at the left side the first spade has the number12 with a negative symbol the next spade has the number 6 with a negative symbol the next spade has the number 15 & no symbol the next & last spade has a + symbol only. any ideas. cheers davef.

It's not a dual 6/12 cylinder tacho is it? - that would explain the 6,12 neg terminals, the + is obviously the power 12v, the other one?, maybe the dash light feed?

This is a guess BTW, if it explodes don't blame me!!

Cheers

Chris