there is a cover behind the foglight, it may have come loose and let water in! please check that first
MB seem to have a problem with these sealed fog lamp units. A work colleague had both his lamps changed on his 51 C220, Both fog were replaced on my 51 C32 last year & the wife's ML has water in her front driving lamps which are going to be replaced at the next service. So the cure is a trip back to the dealer for a Warranty claim.
Outcome The stealership wanted £150 for the part as they don t just supply the seal. Got it done under warranty after argueing the toss. I won t be driving close to the back of many cars in the future.lol Regards Ian
