I just installed a used factory wiper motor, rebuilt the washer pump, regreased and cleaned the whole motor. I then reconnected the battery and it just started working by itself while the switch is in the park position (left) in extremely slow speed. It works in the second position (middle) with the same slow speed and parks in the last position (right). Has anyone had this weird issue?
The wiper switch attaches to the plastic dash. One of the mounting screws has a ground lead that goes over to the light switch. It isn't unusual for that screw to break loose along with that ground lead. Check that first. Without that ground, the wiper motor will seem like it has a mind all it's own.
Will double check all the grounds. I did install a new brass strap to the motor and will check that too.