No heat from passenger side vent

As the temperature has began to drop around here so did the heat in my wife’s car. First only high speed would work but that was an easy fix and replaced the blower motor resister. That is fixed however she is only getting hot air from the driver side vent. The center two vents are warm and the passenger side is cold. Even when I switch to defrost the driver side is hot passenger side is cold same when I switch to the floor. All the actuators seem to work visually. I have only located 3. This vehicle does not have duel climate control so I assume it only has 3 actuators associated with the heater/AC. 1) mode actuator 2) temperature actuator 3) fresh or cabin air actuator. Everything I see online about this issue points to the blend door actuator however they all seem to have dual climate control so I’m confused if this would be my problem since mine doesn’t. Some say it could be the heater core being clogged but I am getting hot air however only on driver side. The amount of air is consistent through all vents so nothing clogged in the vent. I am stumped and could really use some help in identifying my problem. I assume since I don’t have dual temperature control that air would simply pass trough one main vent than through all 4 front vents equally. Does the temperature actuator still control each vent separately even without dual temperature control. Sorry for the book but I am hoping you all can help. Thank you so much.