I talked with a former GM tech about this headlight issue. First off in regards to my problem about DRL's staying on in cold weather he hadn't heard of it, and suspected like I do a switch problem. As far as other headlight/running light/turn signal issues, he suggested checking the wiring bundle behind the windshield washer container, take it out and you will probably find lots of corrosion in the harness, rather common on Cavaliers he says. Good luck
Jeff