I have taken that back off a couple of times to look for and clean the contacts, but I cannot seem to locate them. Does anyone know where I can get an electrical diagram for this pump? The design is kind of a pain in the butt.

Reason for cleaning...I do not have any air in the lines, but when I try to start in normal (high) speed the pump just sputters and shakes. If I take a 2x4 and jolt it (not hard enough to dent) it will take off. I read on here that this is most likely dirty contacts. I have no issue in low speed.