Had the same problem with my Lippard leveling system. Turned out to be a bad Trombetta switch which is used to reverse polarity to run the pump forward and backward.
Here is a link with photos. Find it and look for cracks, damage etc. It is normally with a foot or so of the pump and reservoir. About the size of a pack of cigarettes.
http://www.trombetta.com/products/products-contactors/reverse-polarity
You'll have to copy and paste as I don't know how to make a "clicky"
Good luck
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