What year model and since you have checked the wiring out of the A-Ten, we suspect a loose ground again? Check the terminal strip in the back?Cross run the ground wire of another pump and vice versa from this ground to another pump.See which pump runs, then you have determined which wire is faulty on a connection.Now you can trace that wire and find the error. Wiring is really a very simple process of elimination. Find which wire has no connection, and trace it backwards until you find the find the source. Everyone make it much more difficult than it is. Dont start at the point of origination, work backwards. Good Luck and we hope this helps.BCB