Clio 1.2 - speedo innop - poss speed sensor

Hi there.

Friend of mine has a 1.2 clio.
Its a clio 2, phase 1.

I have had the dash top off to check the wiring is plugged into the speed counter itself, this seems ok.

Where is the speed sensor? I am sure it must be on the gearbox rather than on the brakes?
And i am not sure if the cars abs is working as it skids to a stop rather than the pedal juddering?.

The speedo sometimes flicks up to 7-/80 when on a dual carriageway but then dies off, also we had it working for a few minutes all over the speed range (proper operation) but we got to 50mph and it died again.

Im wondering if this is more of a wiring fault myself..

There was a blown 30AMP fuse in the engine compartment fusebox.

I fear the sensor maybe intermittently giving a reading rather than constantly giving a feed - but i need to know where the sensor is?

Thanks very much for any help / tips,
Paul

The sensor is down the back of the gearbox, its a black plastic unit with the wiring plug on the top, it can be reasonably easly removed.
Fuse F9 under the bonnet is for ABS.