I am having a hard time locking my 91 300TE. I use my key to lock the car and the after the driver's side button goes down it comes right back up. The other doors (passanger, rear, hatch and gas filler door) all would not lock. I sometimes have to walk over to lock the car on the passanger side and than all the doors would lock. I also tried to reach over from the passanger side to manually lock the driver's door but the button would pop back up again after a second! I can hear the vaccum pump running when all the doors would lock from the passanger side.