Rear wiper on my wife’s 15 expedition started moving very slowly then stopped completely.. replaced with a new one…worked when installed .. went to use it again , wouldn’t work … then randomly decides when it wants to work … guy who fixed it said it was all jammed up inside and he lubed it up and put everything back together … any help would be appreciated

 

IIRC, the wiring in the rear hatch needs to be rearranged to keep water from running down the wire ad into the connector.
Route the wire so there is a loop in the wire that is lower than the connector.