Occasionally when you own a car one of the locks will give out for some reason. You can still lock and unlock it by hand, but pressing the automatic locking buttons doesn't work, nor does turning a key in the lock. This can be a significant problem if the lock that failed is the one on the driver's door. Despite what people think this isn't an electrical problem. There's no problem with the fuses. It's the door lock actuator. There's one set into the base of each door lock and sometimes they short out.
Before you replace it, try removing the door's service panel. Admittedly, this is not easy to do with a Ford Ranger given the difficulty in fitting the panel back into place cleanly. It may just be easier to have a repair service replace the actuator. However, some may prefer to expose the actuator behind the service panel and make sure the wires connecting it are securely in place. This could save you both money and time if the wires were simply loose.
Ford Rangers come with remote door openers as a standard. However they can stop working after as little as 15,000 miles on the road. This can happen for a number of reasons. First check the remote to make sure that the battery is charged and touching the contacts so it's sending a signal. Next check the fuse box located near the bottom left hand side of the driver's side footwell. It should be near the base of the steering column. Check to make sure the fuses are all functional with a voltage meter while the engine is running. If no electricity is flowing through any of the fuses, replace them and see if the remote will work. If not, then the only remaining possibility is the control box, which receives and interprets the signal from the remote. This should be on the panel opposite the fuse box, across the steering column. It's not likely that all the wires running from the control box would fail at once, so it would be a fair guess that the control box is faulty or has failed and needs to be replaced.
If the lock itself makes noise, there's something wrong with the door lock actuator. That's about the only thing located in the doors that can go wrong, but it has more than one thing that can go wrong with it. If the lock doesn't work and makes a continuous clicking, ticking, or snapping noise, even when it's not in use, then the problem is electrical in nature. The door lock actuator hasn't seized. Instead, your ground wire has come loose and the noise you hear is caused by electricity as it jumps from the loose wire to a nearby metal service. This must be dealt with immediately as it is a fire hazard. The service panel should be removed and the wires fitted back into the actuator.
