2005 Silverado W/T V6 5-Speed. Chilly this morning in NJ so I had the heat on and was all nice & toasty. Left the slider swithes in the up position when I shut off truck when I got to work. This afternoon not so chilly so I pushed the temp control down but still getting HOT air from the vents. I appreciate any direction as to where to start to look to fix especially before spring actually gets here. Thanx.