The change of seasons sometimes reveals problems with a vehicle that would otherwise go unnoticed. If you have a Jeep Grand Cherokee or Ford Explorer that has an outside air leak behind the glove compartment, you may have a broken fresh air door (also known as a Recirculate Door or Max Door). The fresh air door is used to recirculate air in the passenger compartment or allow fresh air to enter the HVAC (heating, ventilation and air conditioning) system. Surprisingly, the Explorer and Grand Cherokee share a common defect in the heating and air conditioning system. The outside air doors are made of weak plastic that can often break under the stress of the control actuator. When it’s cold outside, this problem becomes very apparent. In warmer climates in summer, a broken fresh air door dramatically reduces the efficiency of the air conditioner.
Checking it It is easy by operating the fresh air door and listening to the increased air flow. When the climate control setting is moved to maximum, the sound of the air blowing through the vents should be louder because the fresh air door is sealing the outside air, forcing the inside air to recirculate. If the sound is not louder, you can open the glove box door and look behind it to see the operation of the door when you change the setting from normal to maximum. If the door is not visibly moving, it is likely broken. Sometimes the door can even fall to the bottom of the box, positioned just above the blower. It may not be visible, sometimes you can stick your fingers through the plastic grill and feel the door come loose at the bottom.
Replacement The door is not a do-it-yourself job. You need to open the dash and remove the HVAC box in Grand Cherokees. On Ford Explorers, the job can be done without removing the casing, but the assembly must be replaced. Obviously, if the case needs to be removed, the refrigerant must be recovered, which requires an AC machine. So if you have mechanical tilt, the one to do at home could be the Explorer, of course this depends on your mechanical ability. Even if you are not doing this job yourself, this information can be used to help explain to the repair shop what the problem is. By providing more information to guide the technician to the problem area, diagnosis time can be reduced.