03 Toyota 4-Runner A/C

This vehicle has passenger side air control. The A/C blows cold for the passenger vents, and warm for the drivers vents. The mode door actuator works properly. What would you suggest to fix this?

How is the zoning done? If it uses dampers, a damper could be stuck. If it uses solenoid refrigerant valves, a valve might be stuck closed. In either case, the control circuit might have a fault.
Is there only one evaporator coil or are there two? That makes a big difference in the way the system is designed.