One suggestion is that you remove the #5 unit and dry out the inside of the headlight. I believe it is the only access point into the headlight. I would then try to discover how the moisture got into the lamp and seal it with epoxy or something like it.
You could take out both bulbs, and funnel some hot air through one bulb apeture from a hair drier or hot air gun on very low setting?
You do need to find out how it got in mind.
Unless the bond between plastic front lens and the body of the light has failed in some way the only other access points are the plastic caps on the back of the bulb apetures, or maybe the parking light bulbs are not seated correctly, they can be tricky.
There is a couple of breather tubes which should be still attached.
The headlight assembly is well shielded against water so it must have taken some doing to get water into it. I've ridden in frog chokers that have drowned my fpc and the BMW accessory taillight but the headlight never gets a drop inside.
Hosing the inside of this bike, especially if you spray it with S-100 or some other detergent that helps wick water into places it wouldn't normally go is a bad idea. If that is the case, there is probably water in the fpc well that needs to be removed before the fpc sucks it in and dies.
Maybe this bike has an HID conversion and the back of the lamp is open- every HID set I've seen seems to need to have those back covers removed.
A hair dryer with bulbs removed will eventually dry it out.
Very rarely a plastic lens can get a hairline stone crack- these are easily seen and patched with clear epoxy rubbed in and buffed ot when hardened= been using one fixed this way on a car for about 5 years now.
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