Ok - so I was having issues with my wiper, in that I was driving in semi-torrential rain on the hwy and the wiper just quit in mid-wipe! I limped home with the hazards on and found this post, which was VERY helpful in pointing me in the right direction. Many of you are talking about greasing up the arms and mechanical parts behind the wiper cover.
This was not my problem. I opened it up and it was greased fine and moving freely. So then I took off the cowl and all the plastic covers to get to the motor and linkage (My motor still was working - I could hear it, so I ruled out fuse/relay issues quickly). The motor ran, but the wiper didn't move. So, I felt around in there and the linkage was kind of loose on the driver's side by the motor. I pulled the whole assembly out and inspected it to find that the linkage was loose on the motor and needed tightening - I tightened it (the motor has splines to make the linkage actually move). This job took ~20 minutes all toll, and cost $0.00. I couldn't bear thinking about laying out a grand or more for this repair, so I tinkered around and figured it out, and I was GLAD I did. PLEASE check yours before dropping tons of money on it - it could be something that simple.
Please see detailed pics below.