My AC fan constantly goes up and down. Its very annoying. Any ideas if this is controlled by a fan speed relay or something that has gone bad?

Thanks,
12vthman

 

Are you talking about the blower inside the cabin?

 

Sounds like a blower motor resistor. .

Was surprised that it goes for $73 on Amazon when you can get it for under $20 on PartsGeek.

Of course I could be mistaken.

 

Yes it is the blower inside the cabin.

 

Thanks for the information. Although, if the blower motor resistor was out would the fan speed fluctuate on its own. It will blow softer and harder randomly.

 

Do you have the auto climate control? If so, I don't think that system uses the resistor, it works off of a circuit board which means big $$$.

 

I do have auto climate control. I found this at Oreilys it says it is for auto climate and control and actually the one I have is for dual climate control.

http://www.oreillyauto.com/site/c/se...2010&make=Ford

$65 not too bad

 

Have a '12 with auto controls but have only used it on heat. The blower will not run until the engine is able to provide heat. It hen increases and blows strong when it is bringing the cabin up to heat and slows when it's near or at the set point.

I believe this is by design and is likely to be the same thing with A/C, is it not?

 

Hi, I have been searching for this type of AC fan problem, i have the same issue. i have an 09 Lariat, dual climate with Navigation screen. my problem is, the fan will erratically change speed ,even when set to max speed it will quickly slowdown and speed up - some times rapidly the some slow down up and down. it happens at start up on hot days, or after temp is stable when speed used to be stable and slow is now erratic. dealership had the dash out for the left actuator, I'm afraid they dropped a ground wire? will trouble shoot this in morning .
what I need help on, is there a calibration for the interior temp sensor? blower speed controller or trouble shooting tips? ideas? thanks for any help/ideas!

 

ok, I gave up looking for troubleshooting information. it seems that I just need a leap of faith, it worked. I replaced the fan speed controller(9L3Z-19E624-AC, , $65 US) and my speeds are correct for the conditions of AC or heating. The controller for dual zone AC is different to the manual fan speed resistor, but most parts houses still list them as speed resistors.