I have a 05 f250 lariat ext cab. The other day I went to put the passenger side window down and it did not do anything. There was no noises or anything to even give a hint it was going bad. I checked the relays n fuses a least the ones that I could find. I pulled the motor and tried it without it being in the regulator it runs up but not down on the passenger side switch but the drivers side nothing. So I swaped the motor still the same. Replace both driver n passenger switches other wise I'm at a loss now.

 

There is a good possibility there may be a broken wire in the boot on the driver's side where the the wire flexes every time the door is opened and closed. The wires switch polarity when each function is selected. You didn't say if the motor worked with both up and down functions when you had the motor out and switched the power connections.