OK, if the lights are on then it is good that there is enough heat to melt the ice which would form in the cold weather you/we are having. The question is if the DTRL's prevent this moisture under normal circumstances, hopefully it does, when water is present it may take a while for them to dry out.
The other question is would 3m film over the lens prevent or decrease this oxidation/hazing. I have had two Chrysler's, one lens was very good with minimal hazing and the other was the worst I have ever seen, it would haze over badly in a few weeks. It all depends on the resin used. My current 300 is very good.