Heat on only the passenger side???

Turned on my heat this morning and it's blowing hot air out of the passenger side like normal but the air coming out of the driver side vents is cool. Happens on both the upper dash vents and lower foot area vents. I also checked the defrost vents and they also blow cooler air (from all vents). My guess would be that its some directional valve behind the dashboard and not something like the heater core or thermostat since I am getting some hot air. Can anyone help?

what year?? There is a tsb for a ac concern I forgot the number and concern but if you have the yr I might be able to check it

the blend air doors may not be working properly, with the engine off and the key on, (assuming it is a newer model, but either way this will help) move the blend air knob from panel all the way to defrost and listen if you can hear the doors changing positions if possible try to get a visual as well do the same thing for the temp control. if it has the electric blend door actuators, pull it off and see if moves when you change positions, if not, you prolly have a bad actuator, make sure the doors move freely. if they are actuated by cable, make sure that the cables are moving the doors and nothing is bound up and broken, and on some models they were controlled by vaccum, make sure you have no broken vacuum lines. without the year or model it is hard to tell, these are just some basic t/s steps

Thanks for the info. Its a 2002 Ram 1500 Quad Cab 4.7L V8
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