The overland model uses the Automatic Zone Control system (AZC). There are no vacuum actuators in the AZC system, only electrical. Also, there are no flow control valves in the system, so even if a valve didn´t work properly, it would not cause airflow problems ( heating problems or mode select problems (windshield/vents/floor) can occur when blend door or mode door has problems. For recirculation door see the text below)
There are two common possibilities;
1) If blower motor controller was changed, then two wires where cross connected and the blower runs backwards, blowing almost no air.
2) The recirculation door hinge broke. The door will be laying on top of the blower motor, blocking almost all airflow. In this case, remove the blower motor and look up. If you see the door, try to move it by hand. If it moves, the hinge(s) is broken. A temporary repair (and for some the final
) is a wire which holds the door up, but you loose the recirculation function. Final repair (changing the recirculation door) requires pulling the complete dash.
Eventhough a melted plug on the blower motor controller is quite common as well, this will normally only be discovered when the blower stops working completely. In this case several speeds can be heard from the blower motor, so the melted plug is not the problem overhere.