Change puddle light , need to know how to take the lens off to change the light bulb in the mirrior of a 2003 ford expedition .

Per the '03 Owners manual...

Approach lamp bulb removal (if equipped)
To change the bulbs:
1. Make sure that all the doors are
closed and the interior lights have
automatically turned off or the
opposite mirror approach lamp has
turned off.
2. With a small flat tipped
screwdriver, insert the tip into the
approach light module slot located
on the outboard corner of the lens
to release the clip.
3. While holding the clip in the release position, pull the approach light
module down.
4. Remove the two wires from the module and replace the module with a
new one.
5. Reverse the order to reassemble the approach light module.

Unless you have the mirrors with the turn signals, they have a Torx head screw, that can be accessed by pushing the mirror forward..