I'll have to agree with BornAgainFordOwner on this one. I'm currently having the same problem on my wagon and I think I've narrowed it down to the left rear door actuator. The best answer I can give you is to get a hand full of fuses and disconnect the plug on each door actuator one at a time and find out which one is blowing the fuse.
2002 Wagon 5-speed & loaded!
2002 ZX3 Black 135 hp X 2
1978 Fairmont Wagon 289/5-speed
1988 Saleen Conv. #368