Tech Tips (by ALL DATA): Dodge Durango experiences HVAC issue
Problem: The vehicle was brought to the shop because the HVAC would only blow though the floor vents. The problem had started a few days prior, and seemed to start happening overnight.
Details: The tech connected a scan tool but didn’t find any DTCs in any modules. He noted that the HVAC system seemed to operate as designed, except when switched to the vent mode. Then it only blew air from the floor vents.
He checked the vacuum source to the HVAC control head; it was okay. He also checked every vacuum hose at the control head; they appeared to be connected correctly and not leaking. At this point he called Tech-Assist.
The Tech-Assist consultant suggested checking downstream from the HVAC control panel for possible vacuum leaks in the lines to the door actuators and checking the actuators themselves for leaks. The tech checked for leaks at the mode & blend door actuators with a hand-held vacuum pump and found the mode door actuator was leaking.
Confirmed Repair: He replaced the mode door actuator and verified that air was blowing through the appropriate vents in each mode and the HVAC system was working as designed. Fixed!