Q: No heat on passenger side

Hello. Most of the time this is due to a failure in the blend door motor on the passenger side. It can also be the door itself or a sensor issue but most of the time it is the motor. This is an electrical motor that moves the blend door to adjust the amount of hot or cold air entering the vehicle. When the motor goes bad it sticks in one position. I usually remove enough of the dash to access it so that I can test it as it can be the control module also. If you are going to have this repaired, consider having a technician from YourMechanic come to your home or office to inspect your heating problem and make the necessary repairs.