Water in E320 lights

My 1997 E320 is showing drops of water condensation in the main and side lights on one side .Can someone please tell me -
a) How this got in?, and
b) How can I get rid of it?.
Thanks. John
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[Slightly off topic]...
I had this problem on my ML350 (and ML320 before that). The dealer messed about for a while and then replaced the whole unit (!) in both cases.
Personally I think that I was too heavy handed with the power washer. That said, there's no direct way for water to get in from the outside (unless you raise the bonnet of course) and so who knows. All that I can tell you is that once it started, it could not be stopped.
I now avoid power washing the area around the lights and use good old elbow grease.
HTH.
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John Craig wrote:

a) There is water condensation in the lights' enclosures due to high ambient humidity and temperature gradients.
b) The seals in the main and side lights are not sitting properly and/or are damaged. I don't know of any solutions to get rid of the condensation other than disassembling the lights' housings and replacing the seals.
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Hernando Correa wrote:

Sorry if I jumped the gun and forgot to add a cautionary note. I am not sure if the housing seals are replaceable. Maybe the light assemblies are factory sealed and then a DIY solution is not practical.
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There is vent in the rear...a little "U" shaped rubber hose fits into the vent nozzle. You can try blowing into that vent with hair dryer, I suppose. You can also try using the hair dryer direct to the front of the outter lens in hopes the heat will cause the condensation to evaporate. These are after-the-fact cures. You may still need to resolve how and why it occured... as it is likely it will reappear if the conditions are right (or wrong).
One could also yank the light assembly and seal the perimeter of the headlight (where the outer lens joins the gray housing) with silicone. I used windshield silicone first...as it is more viscous and allows the goo to seep into the tiny crevices and nooks. This was followed by regular, clear, RTV silicone.
This sealing exercise was done when I retrofitted E55 bixenon HID into my E320 so I had everything all apart anyway....and was in the process of closing and sealing everything up again.
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