wiper box trouble

After studying busterbus's superb photo sequence (thanx Buster!!) i decided to tackle the problem of a non working passenger side wiper. After renewing the box the cable no longer engages with the teeth of the cog in the box, but just skips over them. The problem only occurs if the wipers are attatched. Without wipers the whole thing works wonderfully, as i discovered when i "tested" the set up before i replaced the dashboard!! Dash is now off again but can't locate problem. Any ideas folks??

It sounds like the cable is not making good contact with the wire under load, or is the boss spinning on the shaft?

Had another look and this may sound stupid but....the coils of wire around the cable are orientated like this ////// but teeth on wheel look like this \\\\\ . Is this possibly cause of problem??? by the way it is a britpart replacement part not genuine land rover. could they have put the wheel in the box the wrong way round??
The wheel does not spin independant of the wiper bit - sorry about lack of technical terms.