For a while now my Focus SE windshield wipers (fronts) have had a mind of their own. Regardless of switch position they will go at full speed. Even in the off position. Sometimes they wont come on at all. Usually I just pull out the fuse, number 18 in the engine box, and forget it until it rains. But even then they refuse to go sometimes creating a serious hazard. One thing I have noticed is it does seem to intermittently be tied to the accelerator. For instance, I'll be sitting at a red light and they will being going full speed. As soon as I press the accelerator they will stop for a moment before continuing full speed. They will usually continue even when the car is turned off and keys pulled from the ignition. Only pulling the fuse will turn them off. Another thing I have noticed is that if I have had the fuse out for a while (I live in southern California) and put it back in, I may get a few weeks without issues. I recently replaced the Wiper switch behind the steering wheel to no avail. The fuse looks fine but I'm going to replace that soon. I know there is a fuse in the passenger box that connects to the rain sensor, but I'm not sure my base model even has that and I'm not convinced that removing or replacing either fuse would fix the issue.
I've seen similar issues around but no one seems to have a solid answer.Anyone have ideas?