I just bought a 2002 1500 sport. With out the ac on it only blows hot air. With the ac on it blows hot on the passenger side and cold on the drivers side. Does not change to defrost or floor only through the dash vents. Blower is fine-has all speeds. Also the light does not turnon the control panel when the ac is on and the controls backlight does not light with the dash lights. Seems like there are a few different problems. Anybody have some knowledge on this? Will

 

Welcome to DF
I going to guess either heater control head or bend doors. I will move you post to the 3rd Gen Ram section.