Here's a couple pics of one I modded:
All lit up:
I hate to say, but I had to remove the radio bezel, the black trim around the steering wheel, the lower dash panel & metal brace behind it & the dash panel in front of the gauge cluster to get to the headlight switch.
Once you get to the switch, it only takes a minute to remove the bulb holder/swap the new one in.
You "might" be able to go through the fuse panel, but you'd need tiny/skinny hands to get in there.
From what I understand, Ford doesn't sell just the bulb holder ass'y, they want you to buy the entire switch ass'y. BOO!
I have a couple extra bulb holders for the headlight switch if you only want to remove the dash & stuff one time... some guys send me their bulb holder(s) to mod when I'm out of extras or after they receive their LED modded holders.