For your Expedition, all you have to do is buy the Xenon (HID) bulb kit and install it in your projectors. The difference is between night and day.
Two 10mm screws hold each headlight assembly in place along with a couple of spring clips that fit into holes in the radiator support. you just unscrew the two screws and wiggle the assembly out. You disconnect two plugs and the whole thing comes out. In this picture you can see one of the lower pins the other one is a spring clip.
The large opening is for the low beam bulb the smaller one is for the high beam. I had to cut a 1" diameter hole in the low beam rubber dust cover to accept the rubber grommet for the wiring harness that comes with the kit. I cut out that grey-ish rectangle with my dremel to make room for some other connectors that had to pass into the the housing and then I sealed the opening with high quality electrical tape and layered it like shingles to shed water. Unfortunately I didn't take any pictures and its snowing right now.
This is the kit that I bought and that I recommend.
https://www.xenonhids.com/9005-single-beam-full-xenon-hid-conversion-kit.html
I bought their 55w Galaxy ballast which produce 4200 lumens. I also went for the 5000k color temp which is the pure white. When you start going up in color temp (like 6000k still white but bluer) you start getting into the blues and you lose some brightness.
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I mounted my ballast to the side of the low beam projector housing (the one that extends toward the back of the vehicle and you can see the nice flat surface so that was ideal.
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