Anything that can almost totally 'seal' the assembly from moisture, then before installing them (in the sun facing them towards it), use a hair drier on low & aim the thing into one of the opened lamp covers until you get everything inside very warm. Then, while it is still very warm inside the lamp assembly (you might need an extra hand or two), cover/seal the openings. Do that to the other one and you should be OK.

Thats about the only suggestion I have short of finding a 'kit' somewhere. I am guessing you already made sure those rubber 'vent covers' are intact, with that little foam piece inside them (and you have the rubber covers behind the lamps installed afterwards)? Good luck!


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