Rear wiper & washer
Just fixed my rear wiper and washer.
The rear wiper motor is a completely crap design. It has a hollow wiper arm spindle which is used to pipe water from the rear washer pump to the rear washer jets. The seal in the motor fails, the whole motor then gets filled with washer water and corrodes out the inside. Look on youtube to find out how to remove the trim, wiper motor and rear spoiler.
The wiper motor is driven by the electronics pack fitted to the back of it. Inside here is a solid state relay with current sensing. If the wiper motor is even a little bit sticky and not yet seized this increase of current is sensed and it shuts the motor down.
With your wiper motor in hand, remove the torx screws, open it up and clean out all the crap. Grease it well and reassemble. With a soldering iron de-solder the wire from the electronics pack to the motor. Then connect the motor contact to a battery and an earth to the frame and the motor should then run. If all is OK the current will be <1 amp and it shouldn't sound too laboured.
Solder the wire back on and refit the motor to the tailgate. It should now run OK.
Remove the culprit of all this anguish, "the washer hose that goes into the back of the motor". There is a non-return valve in the hose, mine was blocked solid so clean it out, get a new one or toss it and do without.
On the left top edge of the tailgate is a blank grommet, pop this out punch a hole in it to take the washer hose. Route the washer hose through this grommet into the rear spoiler. I drilled a 10mm hole in the lower edge of the spoiler so I could route the hose through it and back out so that it sprays water on to the rear screen and not into the wiper motor.
Problem fixed.