Speedo wiring help

[CycleSi]

Whilst I have the engine & gearbox out of my car I'm also sorting out some other small jobs.

I'm replacing the speedo drive/sensor in the gearbox, but the wiring on the car itself is 1 x green and 1 x blue + red trace whereas the new part has three wires:

1 x yellow + brown trace, 1 x brown, 1 x black + brown trace.

Can anybody tell me what wire does what so we know what to connect to, etc.

Many thanks, CycleSi

[Jonathan Kay]

What make and model is the new sensor?

Do you already have the wiring diagram for your car? Let me know if you'd like one.

Jonathan

PS Some preliminary guesses:

Green: accessories fused via ignition switch 
Blue/Red: (sometimes used for RH headlamp main beam!)

Brown: should be a feed from the battery
Black/Brown: sometimes used for generator/ alternator to tachometer, so probably sensor to instrument
Yellow/Brown discussed in this thread, but first I'd make sure it's appropriate to your specific model of 7.

[CycleSi]

Hi Jonathan - this is the new sensor:

http://www.burtonpower.com/catalogsearch/result/?q=revfss

I've passed your information onto my car electrician to see what he says but that is very helpful - thanks.

[CycleSi]

Sorry - not sure how to create a proper link to other websites.

[Jonathan Kay]

Sensor: "Wiring: yellow/brown - pickup; brown -ve; brown/black +ve. 8 pulses per revolution".

:-)

Jonathan

[CycleSi]

Brilliant - thanks !