I had a problem with my wipers not turning off once they were on. I found that I had power going to the wiper motor all the time even if the wiper switch was off. I replaced the wiper switch and intermittent timer and eventually found it to be a faulty park switch within the wiper motor itself. I swapped out the wiper motor and its been fine ever since. My car was originally a Colorado car and in my research I found that cars in snow states would occasionally have a bad park switch due to the wipers having to scrape ice and snow off the windshield. There is a plastic gear with metal teeth and the teeth act as a signal to stop the motor when the wipers reach the bottom of the windshield. This plastic gear gets stripped and the metal teeth never trigger the signal to stop. Im not sure if this is your problem but I thought I would share. There is also a time control unit that controls light fade, and itermittent wiper time keeping. good luck
