Hot on one side, cold on the other

I would suggest starting with checking for trouble codes. Passenger and driver each has their own air mix actuator and the side that is not working correctly should have a fault with it.

1. LIST OF OPERATION METHODS

By operating each of the A/C control switches as shown in the below diagram, it is possible to enter the diagnosis check mode.

2. INDICATOR CHECK
a. Turn the ignition switch ON while pressing the A/C control AUTO switch and R/F switch simultaneously.
b. Check that the indicators come on and go off 4 times in succession at 1 second intervals.
NOTE:
After the indicator check is completed, the system enters the DTC mode automatically.

Press the OFF switch to cancel the check mode.

3. DTC CHECK (SENSOR CHECK)
a. After the indicator check is completed, the system enters the DTC check mode automatically.
b. Read the codes displayed on the panel. (Trouble code are outputted at the temperature display.)
c. If the slower display is desired, press the DEF switch and change it to the step operation. Each time the DEF switch is pressed, the display changes by 1 step.

4. CLEARING DTC
a. To clear diagnostic trouble code, there are 2 ways.
1. During sensor check, press the "DEF" switch and "A/C" switch at the same time.
2. Pull the ECU-B fuse in engine room J/B for 20 seconds or longer to clear the DTC memory.

5. ACTUATOR CHECK
a. After entering the DTC check mode (Sensor Check Mode) press the R/F switch.
b. As each damper, motor and relay automatically operate actuator check at 1 second intervals from step No. 1 to No. 10 continuously, check the temperature and air flow from visual and by hand. If the slower display is desired, press the DEF switch and change it to step operation. Each time the DEF switch is pressed, the display changes by 1 step.

Hello, my vehicle has 130,000 miles. the air conditioner was working perfect until a week ago, now every time I turn on the air conditioner, hot air comes out of the driver side. I already added more Freon, but no luck.
Any idea what could be the problem?

Thank you in advance.

You have probably created another problem now. Your original problem was likely one of the temperature blend doors not working, but now you have changed the refrigerant level. It requires a very specific amount of refrigerant. Either too much or too little can damage the system and prevent cold air. have the blend doors checked for operation and have the system totally evacuated and recharged with the correct, weighed charge.

Only warm air on driver side vent all other vents cool air.
Van has manual heat control

we don't have much info on this but check to see if the actuator is stuck or not. i'm sending a generic pic but yours may be on the driver's side. if it's vacuum see if hte vacuum motor is getting vacuum if electric same