The Toyota Sienna was manufactured with optional electric windows, which use an electric motor to turn the window regulator. This motor can wear out and require replacement, which is simple once access to the motor is gained by disassembly of the door panel. Replacing the motor will take the average backyard mechanic about 30 minutes to complete.
Disconnect the battery by turning the positive terminal bolt counterclockwise. Place the terminal away from the battery.
Remove the door panel by turning the interior door handle screws counterclockwise, then turning the arm rest bolts counterclockwise. Remove the power window switch assembly by prying up one corner with a screwdriver and disconnecting the wiring harness adapter plug from the rear of the assembly. Tug at the panel firmly and release the pop rivets that pin in to the metal door frame. These plastic rivets can become brittle over time, so replacement of several is common. Once free of the pop rivets, the door panel will come off.
Remove the power window motor by unplugging it from the wiring harness, then turning the motor's mount bolts counterclockwise. The motor will come out directly away from the window regulator gears.
Replace the motor by placing it into the window regulator gears, then turning the mount bolts clockwise. Reconnect the adapter plug to the motor.
Replace the door panel by pressing it to the pop rivets, tapping each one firmly to seat it into the metal hole. Turn the arm rest bolts and door handle screws clockwise. Plug the power window switch assembly back in and press the assembly into the door panel opening.
Reconnect the battery by turning the positive terminal bolt clockwise.
