Any electrical gremlin genius's in the house?

[rebreath]

Seem to have an interesting one here.weigh in as you see fit...
All electrical works except for drivers window,passenger rear and driver rear.For a while depending on outside temp drivers rear would work fine.No longer.All the motors are working and I have replaced both switches.I Have done continuity testing on drivers side windows and swithches.
Here is the rub....With a window motor(any of them) not connected I get 12 volts at the wire terminals when switch is compressed, but When the terminals are replaced on the motor nothing works.I have tested the motors on a friends car and they all work fine.Is this a "ground" type issue? could it be the ground wire cluster behind the instrument cluster?As it gets warmer, it sure would be nice to be able to open more than one window and the sunroof.A/c is defunct at the moment.thanks in advance for any suggestions.