I have a 93 F-350 XLT, there are power lock switches on the front doors but not back door, but the switches control all doors at once, every door lock and unlocks just fine, except for the passenger rear door, It does not have the stud coming up out of the door like a normal lock would have for manual use, I dont believe this to be an actuator problem but maybe? or are there missing parts inside there, ive been trying to find a door schematic for a while and the onlything i can find is people having problems with the actuators, or weak power, would like to try and fix this on my own if possible, anyone have an idea where to start?