Tachometer plugs ? (and identification of materials...)

[DrPepperFR]

Hello everybody !

I'm the happy owner of a 71'RR i imported in France (sorry for my english BTW).

I discovered the tachometer wasn't functionnal ... because not plugged ! And also a lot of cables were not isolated, etc. That's why we decided to clean and fix that.

I bought the electrical plans of the car, but i don't found my information : where to plug it ?

Here is the photo of the back of the tachometer, if someone can tell how to install it back,
it will be very appreciated.



Where to plug the white and the blue wire ?
The blue is the 12VDC i think, and the White to the negative coil, i'm good ?
But the negative coil, it's the ground isn't !

Also, do you know how to test if the tachometer works before reinstall the dashbord (wich is not very very easy) ? Just to be sure the precedent owner unplug it by mistake and not because it was broken ...

Thanks !