Air conditioner runs when turned off

[Fred27]

During a heavy downpour yesterday the vents started blowing cold air in my Ecoboost 4K. Checked the climate panel to see if the A/C had self-activated as it sometimes does on initial startup, however the indicator was not illuminated. It continued to blow cold air until I reached my destination a mile later. Note: Not my imagination, wife also noted the change and It was definitely blowing much much colder then the external ambient temperature of 72°. Later in the day everything was back to normal operation. Has anyone experienced this?

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[Darnon]

Did you have any of the specific vents selected? If you have no vents selected and the HVAC system is on it functions in automatic mode and will use AC as it determines (regardless of the AC button being illuminated/"On") to reach the set temp.

 

[MakinDoForNow]

Did you have any of the specific vents selected? If you have no vents selected and the HVAC system is on it functions in automatic mode and will use AC as it determines (regardless of the AC button being illuminated/"On") to reach the set temp.

There is a humidistat and if conditions are such that condensate could form on the windshield the AC will be turned on to "defog" the windshield . The temp is adjusted away from the dew point.
Also if raining then recirculate air should help AC dehumidifier process

 

[fossil]

humidity sensor? was it blowing on the windshield?

 

[MakinDoForNow]

humidity sensor? was it blowing on the windshield?

The fan will run very slowly most if not all the time to check air temp, etc generally venting at foot level so it won't be as noticable. When conditions require heat or cool fan speed can automatically increase and use different vents.

 

[Fred27]

Did you have any of the specific vents selected? If you have no vents selected and the HVAC system is on it functions in automatic mode and will use AC as it determines (regardless of the AC button being illuminated/"On") to reach the set temp.

You are correct that in Auto mode the AC and fan speed lights do not operate to indicate status. My Maverick has the Dual Automatic Temperature Control (DATC) system. I have never 'intentionally' placed it in Auto mode even once since new and if you had asked me if there was an auto mode I would have said no. The truck appears to remember the last HVAC settings on restart, with the exception that it will occasionally switch the AC on when it was left off (I have probably used the AC less than a dozen times in 18 months.) Yes, I had manually selected vent and fan speed functions just prior to this event. Could I have unintentionally hit the auto mode as the last action? I don't thinks so, however it was pouring rain and the distraction level was high and it would be the most logical explanation for the observed behavior (i.e., cold air flowing with A/C light off). Thanks for the feedback.

 

[Ozarkbeard]

There is a humidistat and if conditions are such that condensate could form on the windshield the AC will be turned on to "defog" the windshield. The temp is adjusted away from the dew point.

Does it do this even if the system is turned OFF (by pressing the Temp dial)?

 

[Mav_RICK]

Does it do this even if the system is turned OFF (by pressing the Temp dial)?

I know I can shut my AC off on a cool morning with windows open and then later in the day when it’s hotter the AC will be running when I get to the truck after using remote start. AC indicator is off.

 

[dalola]

Yep, it will randomly kick the compressor on even if AC is off...... really annoying. I think I'm smart enough to decide when I want my AC to run.

I agree with poster above that it "senses" certain ambient conditions in the cab, and adjusts itself accordingly. As long as the HVAC system is "ON" it could override the settings currently selected.

 

[Ozarkbeard]

As long as the HVAC system is "ON" it could override the settings currently selected.

So, if one turns the system OFF by depressing the Temp button, you're saying it will not override & turn on the A/C, correct?

 

[dalola]

So, if one turns the system OFF by depressing the Temp button, you're saying it will not override & turn on the A/C, correct?

I won't say never, but I personally have not yet experienced that scenario. Theoretically tho, I suppose it could happen, if the sensor is always activated.

 

[MakinDoForNow]

I won't say never, but I personally have not yet experienced that scenario. Theoretically tho, I suppose it could happen, if the sensor is always activated.

It has been awhile since I read about it but as I remember... it monitors while vehicle is in ready status with sub low speed fan at foot level not to be bothersome and can adjust dampers and condenser to keep cabin air away from dew point and condensate off windshield. (Keep your cabin air filter changed to facilitate this low air flow).

 

[GPSMan]

I've never had it come on while the system power button was off.

But yes I have had it go from fan only to air conditioning if the fan was on any setting other than off.

Also AC lights do not come on if the truck is doing it.

 

[Grabber Rick]

During a heavy downpour yesterday the vents started blowing cold air in my Ecoboost 4K. Checked the climate panel to see if the A/C had self-activated as it sometimes does on initial startup, however the indicator was not illuminated. It continued to blow cold air until I reached my destination a mile later. Note: Not my imagination, wife also noted the change and It was definitely blowing much much colder then the external ambient temperature of 72°. Later in the day everything was back to normal operation. Has anyone experienced this?

What I notice about the Maverick is the fan is always on. On start up you get cold air blowing on you right away. I don't like that at all. I would think being on all the time would wear it out faster. When using A/C sometimes you get to cold so in other cars you shut the fan off then back on when needed. What if your fan motor starts to go bad. You will not be able to shut it off. I had cars where you could smell the fan was getting hot so you shut it off. My 07 Focus makes a noise on low speed setting. I use speed 2 or shut it off.

 

[Grabber Rick]

The fan will run very slowly most if not all the time to check air temp, etc generally venting at foot level so it won't be as noticable. When conditions require heat or cool fan speed can automatically increase and use different vents.

The fan is always on the low speed unless you turn it up faster. I really don't like this. You don't always need a fan to be on.

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