door locks broken

My front driver side door will not unlock or lock from the inside no matter which button you push. The driver side button will lock all of the other doors but it will not unlock them. The passenger side button works fine except that it won't lock or unlock the front driver side door. What is that?

its a 96 explorer xlt if that makes any difference

i just had this problem and replaced the latch for 30 bucks from ford dealership, what happens or at least in my case, the spring inside the latch breaks and i couldnt find this little stupid spring anywhere, so i had to buy the whole new latch

i have the same problem but the driver side door lock wont work no matter what button you push and on the passanger side it will lock and wont unlock. its a 91 explorer. what should i do?