[Mitch Leland]

The C3 fuse is 15 amps, I'm sure you checked that? Maybe there's a drag on the motor creating an overload. What about raising and lowering the window with the door open, does it blow the fuse in this mode? Does the fuse blow on both doors, or just the driver's door?

I show D1 for "power windows front" - 30 amps. Further my 2003 996 sheet shows B6 for "power windows" - 15 amps. I'd be sure you have all the correct fuses in place.