Like others have noted, check condition of the various grounds. Many times with everything being painted we forget about things needing to be grounded. Also make sure your wiper switch inside the car has a good ground. With that said the problem I found with mine was inside the wiper motor. There is what amounts to a set of breaker points under the black, round cover on the wiper motor. Remove the 5 screws holding the black cover down. Note the clocking of the cover with tape or a pencil mark. Gently lift off the cover. On the underside of the cover you'll find these "breaker points". If you have a small flat file, clean the contact points. I suppose sandpaper would work as well. Reassemble the cover onto the wiper body and reinstall the screws. I did this with the wiper motor on the car. Between the grounding and cleaning the contact points, it fixed alot of problems I was having with the wiper motor, including the park feature.