Neither the key nor the remote fob opens the driver's door?

Peculiar issue with the driver's door lock. Neither the key nor the remote fob opens the driver's door. The key won't turn in the lock at all. The key will open the passenger door but the remote won't. The remote will only lock/unlock the doors from inside. Any ideas? I'm thinking the driver's door lock was changed. The fob flashes the lights like it's supposed to but doesn't do anything. Fob battery tests 3.25v. This vehicle requires you to hold the driver's outside door handle open in order to lock the door, presumably to avoid locking the keys in. All the linkage is connected and working. I'm suspecting that the fob isn't programmed to the locks or the antenna for the lock is faulty.