Rev Counter wiring in Cromie

[Ianb]

I am told the rev counter wiring on a cromie consists of 3 wires with a connector under the dash? Does anyone know if this is correct and also if so which is the "Signal " wire ? - I'm trying to get the rev counter on my Nissan CA18DET conversion working and i have the red / yellow wire from the nissan loom which is for the rev counter so i'm guessing that the e30 3 wires are + / - and signal ? in which case i would imagine i connect the yellow / red nissan wire to the signal ( to dash ) connector.

[Brianmoooore]

I am told the rev counter wiring on a cromie consists of 3 wires with a connector under the dash? Does anyone know if this is correct and also if so which is the "Signal " wire ?

There is a three pin plug and socket, and the tacho signal wire is plain black.

- I'm trying to get the rev counter on my Nissan CA18DET conversion working and i have the red / yellow wire from the nissan loom which is for the rev counter so i'm guessing that the e30 3 wires are + / - and signal

Not correct

in which case i would imagine i connect the yellow / red nissan wire to the signal ( to dash ) connector.

It may or may not work, depending on the characteristics of the signal produced by the Nissan, and that required by the BMW.

[Ianb]

It may not work, but as usual having asked on here i have that little bit more knowledge than i did before so I can at least try it. I guess if it doesn't work i'll need to add a resistor of some kind. Thanks Guys much appreciated