A different car I know, but, after I got a headlight cluster replaced on my B5 Passat (HID lights), I noticed that that light unit misted up a lot - for a year - or at least a winter - then was okay. Last month I replaced a sidelight bulb in that same headlight unit - now that side is misting up again! On the factory fit HID lights on the B5 Passat, the mainbeam light rear cover is a flat plate with a thick rubber gasket that is secured by three screws as it is also the mounting for the HID controller for the dipped beam - I too think that the misting issue is related to resealing/reseating this gasket and I think that I will either need to get new gaskets or use "a touch" of silicon grease to solve my problem.
On a lighter (sorry no pun intended) issue, on my wife's 9N Polo, I treated it to new indicator bulbs just before its MOT - then washed it and handed it in - got one advisory "O/S headlight misted up" - I did not refit the screw-on cover correctly (what an incompetant fool!).
On a lighter (sorry no pun intended) issue, on my wife's 9N Polo, I treated it to new indicator bulbs just before its MOT - then washed it and handed it in - got one advisory "O/S headlight misted up" - I did not refit the screw-on cover correctly (what an incompetant fool!).
![[:@]](/forums/styles/seatcupra/oldforumsmileys/furious.gif "Furious [:@]")
It's been made worse since the dealer cleaner the car while it was in for another issue, they must have gone nuts with the jetwash 
