If your rear wiper has stopped working or is not parking correctly try this fix before you go replaceing the motor unit.

First off remove the wiper unit from your jeep, basically the following:
remove the door inner trim
remove the wiper arm
CAREFULLY prise off the plastic outer cover where the wiper arm comes through the door to get at the retaining nut
remove outer retaining nut
unplug loom from motor
remove 2 10mm nuts on top of door (you may have to remove the window latch loom plugs to do this.

Then you can manouver the wiper box/motor out of the door.

Once out you have to remove the cover for the contoller unit to get at all 3 bolts holding it onto the gearbox. It takes a bit of effot to lever off, be careful not to break the 3 plastic retaining tabs.
Once off you should see this:

Remove the 3 silver bolts (torq 25) and CAREFULLY ease the controller board up from the gearbox. The motor power leads go through the board and are fixed and aren’t very flexible, they will break if you lift the board to far up. I lifted mine about 45deg from the gearbox to get at the wiper switch under it. This is what you will see.

On mine the middle wiper hasn’t had good contact with the disc & has causes arcing. Wipe the grease of with paper towel and clean the wiper contacts and the disc contact until they are shiney again, make sure the contacts on the end of the springy wipers are good and clean and you have removed any dark tracks from the disc contact. I used a plastic pan scourer to do this. It is easier if you put something behind the wiper contacts to stop them bending flat as you clean them (I used a spanner under them)

After cleaning

Wipe up any debris and regrease the contacts and disc. Re assemble & refit and hopefully you will have a working rear wiper again.