Here we go!
1st of all, remove the motor from the car..
Then prise off the cover from the back of the unit, please note that some of the clips may break in the process.. once doneyou should be looking at something like this !

As seen in the pic, I have pushed out the main drive shaft for the wiper arm
Once that is removed you can start to remove the workings in this order






Once all these parts have been removed, clean them up ready for refitting...
Now the electrical contacts, when the small white cog is removed, check the condition of the contacts, you cannot see clearly on the picture but there are 2 contacts, 1 ontop of each other.
The lower one should be making contact with the brass pole and the upper one should be in contact with the lower one

If you have a multi meter at hand, check the continuity from the wires to the contacts etc inside the unit. If any the contacts are not in the correct position, give them a 'tweak'
Once you are happy with these, put some LM grease on the gears and rebuild (oh dear Mr Haynes)
RE-BUILD IS THE REVERSE OF REMOVAL !!!

plug them into the car and test.....