Hey everyone, I ve got a question about my air conditioning in my 2001 Durango SLT, 4.7L RWD. It never seems to be blowing as cold as it should, even though I have a brand new compressor and it s full of R134a (so far s I know). I don t believe it s my receiver-drier or accumulator, I don t have the associated smell. It s not the blower motor either. We checked the blend doors inside the dash, they seem to be working properly. It just never gets very cool during these hot summer days in Florida. It blows semi-cool in the mornings and evenings, and it s certainly cold in the winter, but I m roasting in there during the daytime. It should be much colder than it is.
Oh, and I m only getting hot air out of the front passenger side vents no matter what I do with the controls.
What could be the problem here? The pressures were all fine when we filled up the freon, and the blend doors appeared to be working properly when we took the dash apart.
paul h2018-06-27T11:52:20Z
It sounds like a blend door/mode door issue...common issue on newer vehicles or with dual zone setups. If the right side vents only blow hot air, then the hotter air is also mixing with the cold air inside the HVAC system which is why the rest of the vents only blow slightly cool air. Had the same issue on a similar vehicle and resetting the system worked on that case. You can try to reset the system by turning the HVAC controls fully off and turn off the truck...then restart the truck and then set controls to MAX AC ....the HVAC system will go through a series of self tests and then normally resume proper operation. Try the controls in all positions and temp ranges and see if it works better. Or remove the fuse for the HVAC system ...wait several minutes and then reinstall fuse...start truck and see if the controls/vents work as they should and AC airflow blows colder.
If that doesn't work, then you may need a shop or dealer with a DRB III scan tool to check for any HVAC system trouble codes and test the system mode/blend doors for proper operation.The HVAC system has multiple mode doors inside the ductwork operated by electrical actuators controlled by the HVAC dash controls to direct the flow of air to the various vents based on the control settings and also a blend door for the flow of air through or bypassing the heater core which mixes or blends the air flow from the heater core and AC evaporator core which controls the HVAC output air temperature from the vents. Another mode door directs airflow into the system from outside the vehicle or uses interior air in recirculate mode or vent mode.
So it sounds like the mode/blend doors for the dual zone system that directs air flow to the right side may have a bad actuator or other issue...broken linkage, stuck door, bad control switch, etc..or the main blend door is not fully closing off air flow from the heater core. Some owners in hotter climates just install a shutoff /bypass valve in the heater hoses to completely stop the flow of coolant to the heater core which then allows the AC system to blow colder air. I've done that on a few vehicles when it was too costly to fix the HVAC system blend door issue. Apparently a lot of Durango owners had this issue and may require the dash to be removed to get at some of the actuators or doors inside the ductwork. A shutoff/bypass valve installed in the heater hoses is a simpler solution for some.
For best AC output on very hot days, you should use the recirculate mode so that you're not try to cool hotter exterior air once the system has run for a while after first starting. Open the windows or doors for a bit if it's been sitting in the sun to allow the very hot interior air to escape.
Check your cabin air filter, usually located under the glovebox or behind the firewall. Make sure its clean. Make sure freon reads correct pressure Check the condenser coil behind the dash, it's the metal coil that hot air passes through to cool down. If its clogged or dirty on 1 side that could explain lack of cold air, or give you warm air instead of cold. You could also check the evaporator coil, it's the metal coil in the front of your car that the giant fan blows into (not the radiator)
If none of the above a mechanic will need to check the system output, and possibly the components like the orifice tube, dryer/accumulator depends on what car you have.