How do you replace the headlight bulb located on a 1997 Ford Expedition?
Open the hood first!!! Right above the headlight assembly look into the cutouts in front of the brace the coolant reservoir is bolted to, you should be able to see the vertical/horizontal adjustment screw threads. The end of the bolts go through the tabs that hold the headlight assembly into position. You need to lift up on those tabs, they are bent to a 90 degree angle at the top. They have to be slid all the way up, I slid them up and they kind of stopped at one poition, kind of a detent or something, but then came up further with more pressure, so make sure you get it past the first stop. After you've got the tabs all the way up you should be able to push on the rear of the assembly and slide the whole thing out to the front.
Once you slide it out, twist the grey ring counterclockwise. This ring holds the bulb in place. Once you've loosened the ring, the bulb will fall out of the assembly. Unplug it and place the new bulb in. WARNING: DO NOT TOUCH THE GLASS OF THE NEW BULB OR IT WILL QUICKLY BURN OUT.
Procedure also worked on my 1999. Try to keep the bolts from moving when replacing the bulb. They are on gimbals and move in all directions, which makes the reinsertion of the assembly a bit tricky.
There are 2 hex shaped rods protruding from the top of the headlamp assembly. You can see these above the headlight after you open the hood. Just use a small socket (5/16" I believe) and unscrew these 2 rods and the headlight assembly can be removed . . . (it drops out of the front) . . . thereby exposing the headlight bulbs.