So have some condensation in my near side rear light cluster. Did some searching on here and see it’s a common problem with a common solution, drill a small hole to get some airflow going around? So got out there drill in hand but when I removed my light lens I discovered two factory vent holes? They have rubber caps on, when removed leave a little rubber bung with a paper filter over the top. Removed those and two holes into the lens?

So I fired the hairdryer into those for a bit and the condensation cleared.

But it’s made me wonder, wouldn’t it work to simply leave one or both of these caps off? That would provide adequate airflow wouldn’t it? Or is there a reason I don’t want two holes at the back here?

I think it`s to stop water from getting in I also cleared mine by putting the airline on it and just running some air through to clear the lense,

A little condensation will be inevitable as temperatures and humidity fluctuate, even with the fresh air that you’ve just blown in. Leave the caps off and you may get spiders and other assorted insects in there which might be difficult to remove.

I imagine that was the idea before the seals start breaking down and letting in moistures anyway?