Blend door or control problem

[Runaround]

My wife’s’07 model has the dual climate control. Right now it is blowing cool on the drivers side but cooler on the passenger side. Once the truck speeds up the drivers side feels like it isn’t as cool as it is at low speed. Also if I slide the knobs to hot only the passenger side changes, the drivers side temp doesn’t change.
What is my problem or do I have multiple problems?

 

[jws123]

3 potential issues 1 the a/c charge is low will alaways be colder on passenger side when it is. 2 your heater core is also clogged up will be cooler on drivers side hotter on passenger. 3 You have a failed blend door and or actuator all 3 of these are possible on a older ram take it to a local shop have them diag it.

 

[Runaround]

When on heat the drivers side is about the same as the outside temperature but the passenger side gets toasty hot.

 

[Runaround]

Also I doubt the heater core is plugged up because the heater does get really hot on the passenger side and I flush the system every three years and put fresh 70/30 mixture in. The system has never been dirty.
I know the system is a bit low on refrigerant but the passenger side gets much colder than the drivers side. It’s not just a little difference. It feels like the drivers side is just outside air.
Another thing that seems strange is the drivers side feels a little bit cooler at low speeds versus high speed.