What year you're truck My A/C took a long time to kick over and change the vents from heat to A/C and back it was a broken door in the heatiing A/C system it was under warrenty still but what I have been told and read this in something that common for the 2006 Rams.

I don't know if the 2007 and newer if they fixed this but I cant hurt to take a look see.

 

mine must be a broken door also on my 02 cause i have hot air on pass side freezing air on my side , this weeks project