so i searched and couldn't quite find out what exactly to check, and my problem seems kind of unique from the other posts i read.

04 silverado 3/4 ton. manual controls w/ dual climate.

i've had the controls set to AC, full fan, vent. and it will randomly go from vent to defrost and back, sometimes goes to foot vents as well. random, possibly from bumps but its hard to tell cuz you are always hitting another bump every 5 feet on our **** roads. its also blowing cold drivers side, and hot on the passenger side. I'm so pissed off cuz its been warm as hell here and this is the last thing i wanted on my hour long commute.

i gather there is an actuator that is the most likely cause of the differance in heat side to side but the posts i saw were vague on were exactly it is i have to look for it.

thanks