My windshield wipers pivot the correct span (across the windshield edge to edge) but when I turn off the wiper they stop in the middle of the windshield? What the heck is going on??
A bit more context: I had a bushing on my wiper linkage blow out so got a new OE wiper linkage arm and replaced it. I let the wiper pivots cycle a few times and then turn them off, so that they would stop in their resting position. If I mounted the wipers on the pivot splines indexed to this stopped position they would blow off the bottom of the windshield. I then tried to adjust the position on the splines so they would rotate to the correct upper edge. So then they appear to be working fine when they are running (covering the correct span across the windshield with each rotation) but then when I switch them off they go to the bottom and then kinda snap back up and come to rest in the middle of the windshield. Super confused by what's going on!
Went down the deep end and found some info: https://www.youtube.com/watch?v=6USlGHcnB74
And another great explanation of how a wiper motor works: https://www.youtube.com/watch?v=a7qJy8mYi6s
I guess the wiper motor isn't just a basic electric motor because it doesn't just coast to a stop like a regular electric motor does. If it did that the wipers would come to a stop at random locations on the windshield depending on the windshield resistance and when you hit the off switch. The wiper motor needs to stop at the very bottom of the wiper stroke and stop instantly. This is done via 'braking' accomplished using counter electormotive force (Dynamic Braking). Crazy...
The weird thing is that my motor stops the wiper arms in the same location every time, it's just that that locations happens to be the middle of the windshield! So I guess the dynamic braking works, but it's offset somehow?? Is there a way to calibrate the wiper motor then? I'm still so confused haha.