My uncle and mechanicare bothscratching their heads.
I bought a set of clear front turns when I bought the truck (15 months ago) drivers sidestarted taking on water with rain and car washing and would get condensation on the inside of lens.

I just purchased a new set of headlights and turn signals. I installed them at work and drove home (15miles). I took another look and it now has condensation on the inside of the driver side turn signal again.

Can someone give me some info or advice or cause of problem?

 

This seems to be a typical problem with aftermarket lenses. I would try taking the lens out and putting a light bead of blue RTV sealant around all the sealing edges and see what happens from there.

 

I would go the other way. drill a couple holes so the moisture can escape.

Stick a plastic bag out in teh sun and seal it off, what happens?
The moisture in the air condenses on the plastic bag and you see water droplets. Same principle is at work on your lights, drill some breather holes and that should take care of your problem.