Oh wow, you don't happen to have a boat do you...?
However yes you should be able to repair the motor, lightly sand off the corrosion from the armature, and then clean it up as I did, with the new parts from the ebay, it should work. Remember do not put grease in or on the actual motor, grease contact with the commutator quickly causes the graphite bushes to stop conducting.
[QUOTE=johnxsi;3353020]Just found this thread and have to give a big thanks to Chrisay for the write up. I was having the same problem with the rear door in my '08 outback, and decided to dismantle today.
Apparently I had the opposite problem to everyone else; not a drop of grease to be found in the assembly. Motor was completely seized. I don't think the ebay replacement will save me here