It purpose of the Ford door mirror is to help the driver easily see what is approaching their vehicle from the rear. This is one of the many safety devices now standard on this type of car and truck. Most vehicles today have one on each of the front doors so what is approach both sides of the vehicle can be seen. The manual door mirror is not something that wears out and requires replacement. The components of this part that tend to break are the levers, cables, and electronics that are housed on the inside so the mirror glass can be moved remotely by the driver of the Ford car or truck. If the lever portion of the door mirror is broken the entire component will need to be replaced. If the Ford door mirror is controlled by an electrical motor, then the relay, switch, and motors need to be checked to properly diagnose the faulty part. The replacement of the door mirror on your Ford can often be completed by the owner. With the glass portion of the window in the up position the first step is to remove the inner door panel and all of the components on it. If you have any electrical components in the door, disconnect the battery first. If there is a lever, cable, or wires leading to the mirror they should be disconnected. The door mirror itself should only be held in place by two nuts connected to studs on the base of the mirror. These have to be removed and the mirror should come off. Place the replacement part is on the car or truck. Make sure you use the rubber pad that should be in between the mirror and the body is in place so the finish on the Ford will not be damaged. Reattached everything you took off in reverse order and you have completed this simple task.