Not enough heat in winter, ac blows cold from one vent in the summer

Last winter I wasn't getting enough heat. It would only blow hot from the vent near the driver's door. All vents would blow cold if stopped at idle for a bit. I thought clogged heater core but after a flush I don't think that was it. Now it is getting warm and I turn on the a/c, it only blows cold air from the vent to the right of the stereo. The vents by the front door windows blow about outside temp air? I'm at a loss. Could this be the blend door actuator? I'm at a loss. Your input would be much appreciated by this shade tree mechanic.

 

Sounds like low coolant level and low refrigerant level.

Are you 100% certain the coolant is full? Check the cap for a full tank and that the burp tank is full.

Same question about the refrigerant.

How many miles are on this vehicle? Evaporator leak is a common high mileage condition and can be temporarily rectified by a refrigerant refill.

I thought I had a blend door servo problem until the coolant and refrigerant were refilled.

Gradual coolant loss (consumption) over time is a symptom of a blown head gasket, a common occurrence on early gen4 vehicles.