The wipers on our Jeep Wrangler stopped working. I removed the wiper motor to fix the problem. It was a greasy, fussy job, but I was successful.

Remove the 4 screws on the plate covering the transmission. In the photo I've already moved the screws.

Inside on the big gear are two copper contact rings. Note the two pits on the outer ring about 8 o'clock. Gradually the copper was burned away by the motor switching on and off. Now there is no contact and so the wiper switch is unable to detect when the motor is in the parking position. This causes the wiper blades not to park, and the intermittent wipe doesn't work either.

A similar photo of the pits worn in the wiper motor gear contact ring.

These are the contact in the cover plate. They look messy, but all that is necessary is that these copper contacts push against the contact rings on the gear. The pits in the contact ring prevent the circuit from closing for one contact.

Covering the motor is a rubber boot. The new motor requires that you install the old boot in order for the warranty to be honored. I'm not sure how they would know. The boot was so difficult to remove that I ended up cutting it off.

The boot is basically useless as far as I can tell. The boot does not keep the motor dry, and even worse, holds water against the motor housing. When I replaced my motor, I used some GM non-hardening spray undercoating all over the motor to help water-proof it.