Groverson Posted July 29, 2020 Share Posted July 29, 2020 So I have been having this issue that seems common amongst the Navigators. Every now and then the AC will stop blowing through the main AC vents and only comes out cold through the defrost top vents. From what I can see under the hood is a vacuum line that goes to this actuator (see pics) that controls the blend door. - I think? The vacuum tube from the actuator heads into the firewall. so I can't see beyond that. I noticed that when I start up the Nav and have my AC on, the rod attached to the actuator will close, and I will get cold air blowing from the main vents. When the cold air blows only through he defrost vents I noticed that the rod attached to the actuator will remain open. ( see pics) Do you think I should replace this vacuum actuator since I can see much beyond this?. I don't see any cracks on the vacuum line in the engine compartment. Quote Link to comment Share on other sites More sharing options...
YT90SC Posted July 29, 2020 Share Posted July 29, 2020 (edited) The vacuum system is made of the EATC control head, the lines, a check valve near the engine, a reservoir and door vacuum servos for the mode (floor, defrost,vent), recirculation door and the water shutoff. That is the water shutoff, not a blend door. In MAX AC vacuum is supplied to the recirculation door in the cabin and to the water valve in addition to the mode door to move it to VENT. What you are seeing in the valve is a symptom, most likely. IF you think it is the valve, just plug the vacuum line with a golf tee and retest. You have a vacuum leak or a failure of the vacuum control part of the EATC. The blend door, which sets the temp of the air, is controlled by an electric motor. Edited July 29, 2020 by YT90SC Quote Link to comment Share on other sites More sharing options...
Groverson Posted August 16, 2020 Author Share Posted August 16, 2020 I have been trying to find the vacuum leaks this issue. This symptom is interesting. What are your thoughts? So I have been driving the Navigator and noticed that this will happens 100% of the time..... When I start it up in the morning(engine cold) the AC will blow through the main vents...Always. When I head out and stop off somewhere and start it up with the engine warm the ac only blow out through the defrost vents....Always. Curious what you experts think? Quote Link to comment Share on other sites More sharing options...
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