2001 Ford Explorer keypad on door will not unlock/lock the front door. It will unlock/lock the other doors

Would there be a loose wire? Could it be a fuse? If so anyone know which one? Or could it be something else? I'm trying to fix my aunts car so they don't have to take it somewhere.

Loose wire, could be, Fuse, probably not. Could also be a bad actuator. This would be the most likely problem.

Its probably the door actuator in the door. Given that door is opened the most that actuator gets the most wear. If the actuators are the same for all doors you could just swap it with one of the other doors. That would be less of an inconvenience and would solve the issue cheap.