Recently, I am experiencing a heater situation. The passenger side blows hot, but the driver side remains ambient outside air temp. The blower runs fine and the volume of air is good on both sides. The automatic controls sync well, and with the temp and blower on HI settings, both the upper and footwell sides are warm…passenger side only. I can hear the blend door changing when changing the settings from upper body to heat. However, when the system goes to recirculation, the problem resolves itself and I get driver side heat (upper and lower)again…What is happening here? Is it me or is there a gremiln in the system?