I have a 2004 Buick Le Sabre Custom, 3.8 V-6, automatic transmission. Hot air blows out the drivers side a/c, but, cold on the passenger side. Only 1 zone to control, so, it doesn't make a whole lot of sense to me.
Any info would be greatly appreciated, as it is currently in the 90'*

Sounds like a blend door actuator has gone bad.

Thank you. I will look into it.

Is it Automatic temperature controls? If so it will have a left and a right temperature door actuator, regardless of having 1 or 2 zones to control.

No, manual controls for temperature & fan speed, both on sliders, left to right.

Sliders are manual.

Correct

You are low on Freon. They all do this when they're low. Don't over think it.

I will check Freon first. Thank you.

Checking the refrigerant charge is definitely an easier step than crawling under the dash, however, when refrigerant is low the result is usually warmer air all around, not half cold and half warm.