Wanted to get some idea of the revs of the car so thought I'd put the tacho in.

It's an ETB one.

On the back there are four connector (plus the bulb ones).

They are labelled as:
+
12W
-
24W (label stamped but not painted in).

I know that I take a wire from the - of the coil. But no idea which this goes on. I'm guessing the - but don't wanna make a mistake.
Obviously I also need an earth but goodness knows which one this goes on!
And what are the other for?

This is with a Premier Loom by the way.

Thanks!
James

P.S. Already tried ETB but they're not answering the phone.

This is purely guesswork, but I would suggest that the + and - are for 12volts and earth.
The 12W I should think would be from the coil as this would be the switched signal. If no joy then maybe the 24W to coil.

The plus and minus signs usually mean battery voltage and earth.

instructions 4 u
http://www.etbinstruments.com/ETB_Gauge_Wiring_PDF/100mm_ETB_Tacho_wire.pdf

Thanks guys.

Wired it up as per Spyderman's plans and worked fine.

Thanks for the diagram Keets. Couldn't understand how that diag' was so different from my gauge... turns out the 80mm is significantly different from the 100mm gauge.

Thanks!
James