How to repace the lower mirror

SOURCE: i need to replace passenger side mirror on 97 ford expedition

Both above answers are not right... I just replaced the Pass side power mirror assembly on my 97 Expedition. No heat, no directional.
The inside door panel must come off.
1. pry off interior triangular plastic trim piece inside of door at mirror area. Remove door panel screw at this area.
2. Pry off power window switch panel and remove door panel screw at this area.
3.Remove interior door light cover and remove screw at this area.
4. Remove plastic cover at door handle.
5. The interior door panel can now be lifted up to release it from it's fasteners.
6. Disconnect light and push power window switch assembly through the door panel and it can be set aside.
7. Disconnect mirror power at coupler.
8 Loosen three mirror mounting screws with 7/16 socket. DO NOT unscrew completely.. the will fall down the door cavity. Use a round magnet on holder to remove the screws completely.
9.Thread electrical connection into door panel and install mirror.
10. Smile when mirror works and drink a beer!
rayman

SOURCE: 2008 Ford Fusion Wing Mirror Replacement

I checked Ford Focus mirror replacement and it seems to be the same. This is for the manual, unheated mirror.

Remove the mirror cover inside the door - slide a screwdriver behind the cover and pry loose carefully.

Remove the single 10mm bolt and the mirror comes free.
NB. Do not drop the bolt into the door.

SOURCE: Passenger side mirror replacement procedures

If its a power mirror there is more thing you will have to remove to get to the wires but if not there is a screw on the corner piece on the inside of the door. just pull the screw out and the bolts (3) that hold the mirror on are behind it. If it power then you will have to remove the door panel to access the wiring to disconnect it

SOURCE: 2002 Ford Explorer - Drivers side door lock, rear

Aside from the fuses, your drive side power door lock may be failing to work because of a bad door-lock relay system, or, alternatively, the locking switch/button, itself, is not malfunctioning and in need of replacement.

A great handyman site that specifies the above probable causes and more is the following link:
http://yourhandymanzone.com/Your_Handyman_Zone_How_To_Pages_Vehicle_Car_Zone_Cars_Trucks_Vans_Locks_Power_Locks_Do_Not_Lock_When_Pressing_Locking_Switch_Button.htm

Good luck!

SOURCE: how to install passenger side view mirror Ford

On the inside trim, you can remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you'll need to manipulate the panel and disconnect the door handle linkage from the door handle and disconnect the wiring for your controls. Then you can access the bolts that secure the mirror onto the door