Cadillac DTS no heat on passenger side despite functioning heater core and working servo on Cadillac DTS

Some Cadillac DTS owners report experiencing a lack of heat on the passenger side despite having a functioning heater core and operational servo. This issue may arise from a clogged heater core, where rust or mineral deposits block the flow of hot coolant. Additionally, low coolant levels can prevent coolant from reaching the heater core, leading to insufficient heat. A dirty or clogged cooling system can further impact heating efficiency, while a faulty or stuck blend door actuator may result in uneven heating distribution between the driver and passenger sides. In some cases, malfunctioning HVAC system sensors can fail to accurately monitor air temperature, contributing to temperature imbalances. Lastly, issues with the blend door itself can disrupt airflow and temperature control, exacerbating the heating problem. For effective resolution, owners are advised to inspect these components and seek professional assistance if necessary.