Before ruling out fuses, try installing gold-plated ones. The silver fuses the factory installed in my 300D's have caused many problems w/ windows and sunroof not operating. I could fix that by sanding the fuse tips, but eventually gave up on the silver's. In your case, perhaps the front window motors require more current than the rears, though strange both circuits would fail at the same time.

Next time you unplug the switch, use a multimeter on the switch pins. If a "voltage loss" issue, you will need to monitor w/ the switch connected, which you can do by pulling the connector back enough to get at the pins. That is how I found my 12 V supply from the fuse panel was getting drawn down the first time I had issues. If you pull the door panel, you will find a terminal for the motor wires (if like my 1985). Verify continuity of the wire from the switch. In one car, a wire had broken where they bend at the door pivot.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans