My father-in-law bought a used 2014 Explorer Sport a couple years ago. The headlights were always a little lack luster but they got worse and worse. He asked me and I pointed him to Diode Dynamics SL1 bulbs as being top quality (have them in my WRX).
So he brings it over and it turns out the previous owner obviously just threw some HIDs in, despite them not being HID projectors. Additionally, there's some broken clips on the housing and the bulbs are stuck in the housing WAY too tight where the new ones would only go in cock-eyed. I think the retention bracket for the bulb was aftermarket and torqued down too tight. We ripped out the old stuff and once we worked around the mods, we finally got a good install. The initial light output and cutoff looked great.
When we checked the beam pattern it still seemed off. There's quite a bit of scatter/glare and there are some huge dark spots in the pattern right where the hot spots should be. We tinkered with the vertical adjustment briefly before we realized it wasn't going to fix the issue. So I begin to inspect the projector lenses and I think I realize the actual issue right away. The lenses are VERY hazy, have some weird swirl marks. I can even make out what looks like a fingerprint and maybe some kind of pattern from a towel or something. So I'm thinking the previous owner pulled open the housing, not sure why... He marked up the lenses, did a crappy job cleaning them off and I'm pretty sure the HIDs might have given off some extra heat that caused some glazing to the lens internally.
*DEEP BREATH* All that to say... what would be the best way to correct this? Looking up replacement assemblies, it looks like it's going to be $800-$1000 for OEM quality replacements... not stoked about that. Father-in-law found some cheap Ebay assemblies in the $250-$400 range but that makes me nervous.. any experience with these? Another option maybe, just replacing the lenses? I imagine that's not readily available though and might cost as much as assemblies. So I'm just trying to flesh out the realistic options. Mother-in-law doesn't have great night-vision so we really need the most practical fix that won't put us back in the same boat. All ideas welcome!