AC Fan Speed Changing Automatically?

[Ford Motor Company]

Fan increases speed randomly. Screen says speed = 1, but blowing much stronger. Adjusting speed makes no difference. Turning air system on/off makes no difference. Phone not on, Bluetooth not on. Will eventually go back to normal.

Hi there! Will you send us a message with your VIN and your local Ford dealer? I can look into things on my end.

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[Tom 71 Maverick 24]

Fan increases speed randomly. Screen says speed = 1, but blowing much stronger. Adjusting speed makes no difference. Turning air system on/off makes no difference. Phone not on, Bluetooth not on. Will eventually go back to normal.

It 'might' be switching to a defrost mode for the windshield if it is humid out - I don't really know this, but that's something to consider. I did notice mine redirecting air to the defroster vents below the windshield without my selecting the defrost vents on the controls. If it does that, the fan may increase speed to hasten the clearing of the windshield before it becomes a problem.

I'm saying "might" because I really don't know what all automatic features they toss into these vehicles today. I generally don't like that trend.

 

[Ozarkbeard]

One possibility: The HVAC sensors might have determined (correctly or incorrectly) that the evap. coil is freezing over. So it increases the fan speed to prevent a coil freeze-up.

Or the all-knowing vehicle computers/sensors really don't know wtf they're doing.

 

[Tom 71 Maverick 24]

One possibility: The HVAC sensors might have determined (correctly or incorrectly) that the evap. coil is freezing over. So it increases the fan speed to prevent a coil freeze-up.

Or the all-knowing vehicle computers/sensors really don't know wtf they're doing.

Both are quite possible. Yeah, keeping the evap coil from icing up is important. Blocks airflow, and if that happens, you probably get little or no air through any vents.

 

[HeyBales]

Since there is a humidity sensor too, that ability even with no auto-mode, to auto-clear the windshield as safety things makes sense.
Though mine failed that last weekend doing some parking lot movement - so perhaps not fast enough yet.

The evap coil freeze over is good one too.
Reviewing the comments it's usually about no auto-mode and fan set to 1 - not always comments about AC being on or off.

Also - are these Dual systems or single control systems - seems like that could make a difference?

I'll take a look at Forscan Lite PIDs to see if anything on evap temp.
There are all kinds regarding fan from several different modules.

For 24MY, the manual mentions this, and doesn't recirc mode sound louder like the fan speed went up?

SWITCHING RECIRCULATED AIR ON AND OFF

Press the button to recirculate air currently in the passenger compartment.
Note: Recirculated air may turn off automatically, or prevent you from switching on in all air flow modes except MAX A/C to reduce the risk of fogging. Recirculation may also turn on and off automatically in various air distribution control combinations to improve heating or cooling efficiency.

 

[Geppetto]

One possibility: The HVAC sensors might have determined (correctly or incorrectly) that the evap. coil is freezing over. So it increases the fan speed to prevent a coil freeze-up.

Or the all-knowing vehicle computers/sensors really don't know wtf they're doing.

Freezing over was one of the thoughts I had.

 

[Dad]

Here's a thought. Could it be the cabin filter is gummed up and needs replacing? Perhaps the fan is trying to overcompensate. Easy enough to check.

 

[FischAutoTechGarten]

I suspect that the automatic climate control of my Maverick Lariat is sentient; as it seems to do what it wants at times, regardless of the setpoints I've set

 

[Geppetto]

Hi there! Will you send us a message with your VIN and your local Ford dealer? I can look into things on my end.

 

[Geppetto]

3FTTW8S92RRA72286 Krouse Ford Woodstock GA. Thank you for your concern. As I cannot repeat this failure mode, unless there is a known fix for this I'd rather not take in in to a dealer.

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