My windshield wiper motor doesn't work. sometimes it will work when i turn it on high but the wipers will just move about an inch then stop. I can wait about 5 mins then do it again and it will move about another inch untill the wipers start on their way down then they go almost normal speed. I checked all the conections and they are fine. I have the motor diasaembled right now the brushes are just fine i think there is something wrong with er motor. what should i do/look for?