Vehicle: 2000 Dodge Durango,
4WD, V8-4.7L, VIN N, Automatic Transmission
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
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
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