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It sounds like you have a bad blend door actuator that is stuck in the cold position.
Do you plan to repair it yourself?
You have two options:
You can replace the blend door actuators and hope that fixes it.
You can scan the system for faults, reset the HVAC module and blend door actuators, and then see if it cures the problem (this requires a compatible scan tool).
Which do you want to do?
Do the vents on the passenger side work normally?