VDO Tacho Help
There should be 3 wires coming from the tacho, a positive wire, a ground wire and a wire that goes to the negative lead on the ignition coil.
wire the positive wire into the power supply wire for the radio, the ground wire to earth somewhere, and there should be a plug for the ignition coil lead next to the master cylinder, near where the main loom comes out into the engine bay. just plug the wire from your tacho into this.
at least, this worked for my EA!
the plug going to the ignition coil only has one wire. on mine it was red, I think.
Hope this helps...