OK, I dropped the headliner in the back, found the motor and control module. Can't see anyplace to insert a 4mm hex wrench or release a clutch, though. Still looking.

It'* definitely not the switch. I guess that leaves either the control module or the motor. Now that the headliner is down, I'm as far as I can go. Time to take it to a shop. Just wish I could crank it closed by hand but can't find anyplace to do that.

Look at the end of the motor shaft for a 4mm hex.