I have tried it also with airlines and bulbs removed also with hair dryer come to conclusion I have a dodgy seal on the headlight I read on here power washing doesn't help it much either lol
washing a car full stop can cause condensation if the water is cold, it makes the lense colder and then as air in the headlight cools.....
or simply, power washing may mean any poor seals let water in!
in your case, when you use hair dryer does the condensation not go at all? or does it go and come back? if it doesnt go at all its water that defies the laws and physics!

