The rear wiper was getting erratic sometimes go, sometimes stop half way, sometimes go with a push. Then no go at all.
Decided to have a try at fixing it. Rear cover needs a long 300mm screwdriver to reach the back clips to get it off after finding all the screws. The box came off easily , one nut for the blade, three hex bolts for the motor.
A 15 torx screwdiver took off the seven cover screws.
At the wiper end of the shaft there is a circlip under the muck.
Mark where all the bits inside are pointing then tap the shaft till it all comes out. The orange tooth wheel came out when gripped with molegrips.
The problem was then seen in the metal circular plate fixed under the orange wheel. Rust and corrosion had made the contacts useless. First tried sandpaper which would have been ok if the metal had not been so pitted. Could have tried it but couldnt be bothered having to take it all out again if it did not work.
Gently levered the tabs on the metal plate till it comes out. Thought turning it over would do the trick but the tabs dont line up. Bent the tabs carefully through to the other side and with a soldering iron pressed the plate down over the tabs ,till the heat melted the plastic and the tabs made neat holes for themselves in the right place.
Put it all back together with lots of coppergrease , a touch of glue on the washer pipe connector, switched on ignition , wiper motor went briefly till parked, bolted the wiper arm back on at the parked position. Wiped grease off kitchen floor, now having coffee.