I have an erratic situation with my passenger door. Sometimes when I use the remote to lock the doors the passenger door will not lock. The only way I have been able to get it to lock is to turn the little white slotted plastic piece on the inside of the door where it latches to the frame. If I do that, the door will lock however when I return to the car it will not unlock by the remote. The only way I can unlock it is by reaching over and pulling the handle on the inside. Any suggestions?