It is over 100 here during the summer, so I just leave the air conditioner on high and max. Until recently, when I flip to max, the recirculate light comes on and that's the coldest setting. After a few minutes of driving, I'll not feel cool or I can tell it's not recirculating, and look down to see the yellow light is not on. I can turn it back on and get cold again, but I don't know why it is turning off the recirculate.

Any ideas? Is the a/c about to go out? If so, Truck For Sale, Gently Used.

 

my '06 has always done this. I assumed it was a feature so it wouldnt freeze itself up....if I leave my basement dehumidifier on max, after awhile it ices up & stops working. Same theory perhaps?

 

Mine works fine, and it does make the air colder as its recirculating cab air instead of outside air. Dont use it all of the time, but behind diesel truck it helps too.

 

I noticed that the recirc feature doesnt stay on with the heater either. When it is -20degrees in January and I press recirc for faster heat, it shuts off after awhile.
Always thought it was designed this way.

 

I'm thinkin' its a deliberate safety "feature" in case exhaust gasses leak into the cab. I rarely use it anyway, even when temps are over 110 degrees, to avoid condensate being left in the unit forming mold. I use it only if the unit is importing an obnoxious oder into the cab or it gets unusually humid and I need to get rid of the extra moisture in the air, both for comfort and to avoid mold.

 

I use mine most of the time. I don't think it should be shutting off. I would have it looked at. If a system freezes up it's because it's low on refridgerant or its a dirty filter. I don't know if the F150's have a cab filter. I'm sure the Mark Lt's do. If I were you I would first check the filter if it has one then maybe check the charge in the A/C system. If neither of those things are the problem it could be an electrical issue.

 

Mine runs in Recirc 100%. I use it all the time here in Texas. the temp of the air coming from the vents doesn't seem any colder, but the temp in the cab gets cooler quicker.

A friends F150 had a problem where his HVAC controls would shut off and come back on in 20-30 second intervals. We disconnected the battery for 10 minutes and reset it, no problems after. You may try that before you do anything.

 

Incorrect info removed.

 

When I'm in max a/c my recirculate mode comes on automatically. The circ mode recycles the air in the cab. Just like your central air recycles the air in your house. You don't keep windows open in your house when you run your a/c. Trucks aren't air tight so you don't have to worry about passing out from lack of oxygen. You won't have excess humidity in the cab when you run in recirc mode because the air in the cab has already been dehumidified by the evap and continues to even in the recirc mode. In essence the air is less humid then any outside air. You may get some droplets because of condensation but that should be the only reason. You get much colder air in the recirc mode because you are pushing cold air across an already cold evap coil. Think of your trucks a/c as a mini central air like you have in your house. Lime1GT I do HVAC for a living so not trying to start a fight just giving some advice. For the most part like I tell most of my customers you have to find what settings are comfortable for you. Some people like 72 degrees others like 68.

 

I stand corrected and have edited my previous reply OptimusF150.
As I use panel/floor for a/c in my 02 F150 I have no option to use Recirc in that mode.

I did reread my owners manual for my 05 stang which allows control of the recirc door in any position except defrost and have a better understanding of max a/c. That being said, a couple of suggestions in the manual under operating tips; "To improve the a/c cool down, drive with the windows slightly open for 2-3 minutes after start up or until vehicle has been "aired out"." "To reduce humidity build up inside the vehicle, do not drive with the airflow selector in the O (Off) position or with recirculated air engaged."

 

Lime1GT I do know what you mean when you first start the truck if you roll the windows down it will get rid of the hot air faster. I do that myself I will roll them all the way down turn on the a/c and drive a minute then roll the windows back up. I don't know how your stangs a/c operates. In my 07 F150 I can use the recirc in any position. I still don't see how the recirc will not get rid of the humidity. In my opinion it seems that when you run the recirc you are recycling the air inside which should have less humidity then the outside air. But hey if it works for you and you are comfortable go with what works for your vehicles.