I searched before I did mine and could not find any info unless I missed it so here goes:

On my 08 F150 I have the round factory fog lights like most and of course with 20k miles I was bound to get a crack in one sooner or later and finally it happened which wasn't as bad as the moisture that fogged up the inside after-wards. So, it was time to swap out for a new one.

Since these are plastic I went the cheap route and got a replacement TYC brand knock off, from eBay for under $20.

Start by crawling under the front bumper and locate the three 10 mm bolts that hold the fog light and the mounting bracket to the bumper, this bracket is also plastic. 2 bolts in the top, 1 in the bottom, remove all 3. Then pull out the plastic "rivet" holding the wiring harness to the bracket, then remove the bulb w/harness and let hang being carefull not to touch the bulb with your fingers. At this time the entire housing can be removed to your work table. You will now notice the light housing is held in by 2 snap in "ears" on each opposite side and the one adjusting screw at the bottom, slide a screw driver under the ears holding the fog light in one side at a time until free, then before you unscrew the adjusting screw, mark its factory location w/a sharpie in the position where it was so your light will be pretty much in alignment when you re-install. Then back the alignment screw all the way out until the screw falls free, at this time you can remove the old cracked housing from the plastic bracket. Insert new housing, snap in each ear one at a time, then reassemble the adjusting screw noting your original mark, reinstall the housing w/bracket in reverse as the removal instructions and viola, you hould be golden. While I was under there since I had never did it I adjusted the lights upward some since they seemed to shine to close to the front of the truck. YMMV!