Wow, that's so cool it's an accessible place! You'd think a spot on the positioner band would trip a limit switch one way or register up with being on the test scan strip the other, but neither is happening because...I mean, did you try to get test leads on the photointerrupter or leaf switch in there? Do that. And if there's paper in the way, laugh and remove that. As if you've been loading papercraft angora sweaters in to print...Brother expect you to go hard like that.Doesn't help. The scanning lamp still tries to move to the left wall instead of the scanning area.
Have you seen the video? Brother support won't help here. This looks like a planned malfunction.