2001 Dodge Caravan loss of pwr to windows, radio, blower mo

For a month now we lose power to the front wipers, radio, power windows, power mirrors and blower motor. And then it works and then it stops. Took to dealership because of build up on battery terminal. They replaced one of the clamps and said it was most likely due to that and the wire harness because there was an "electrical jump between the wires". Well, after getting it home, it happened the next day. Only after the car has a chance to warm up, the power comes back on. Any ideas. Possible ignition switch?
We live in Michigan and have had a pretty brutal winter as far as cold weather goes, but even sittin gin the garage, the problem seems to occur, unfortunately, we cannot recreate the prolem at will.