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A/C fan surging


fazzman
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When a/c is on i can hear the interior blower fan increase and decrease in speed constantly. No matter what speed i have the system set to. Also get a ticking fan noise from inside the dash. Faint cricket type of sound. Under warranty still but just checking to see if anyone else has experienced this.

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When a/c is on i can hear the interior blower fan increase and decrease in speed constantly. No matter what speed i have the system set to. Also get a ticking fan noise from inside the dash. Faint cricket type of sound. Under warranty still but just checking to see if anyone else has experienced this.

 

Hi fazzman,

 

I'm Crystal, the Ford Service rep on this forum. I'd recommend making an appointment for your dealer to check this out; don't forget to come back and post your results. What's your vehicle's model year and mileage?

 

Crystal

Edited by FordService
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  • 2 weeks later...

This happens to mine, too.  Seems like the fan blows at 85-90% most of the time but then randomly it will start blowing much harder.  And it's evident because the cabin gets louder and more air comes out.  Wish it blew at 100% all the time!

 

e: I should pull video from the dashcam when this happens.

Edited by bigalpha
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They didn't find anything. Of course. The ticking noise did go away on its own. The fan is still blowing odd.

In other cars I've owned, (usually without a cabin air filter) a ticking noise is usually due to some debris (insect, edge of a dried-out foam gasket, a maple 'helicopter' seed, leaf, or small twig, lodged somewhere near the fan and what you hear is the debris being struck repeatedly by the fan blades. In most cases, eventually it is struck enough times to dislodge, or it wears away enough that the ticking stops. Or you or the dealer disassemble things until you locate and remove it.

 

In one car, a clogged AC drain hose during hot humid weather to caused the bottom of the fan enclosure to fill with enough water to make a ticking sound. Then I turned a corner sharply and got a wet foot and the ticking stopped. That was when I discovered the clogged drain hose and cleared it.

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  • 2 months later...

Did anyone with this issue find a resolution? My 2013 SE does it too, and I took it in a few months ago, but the dealer said they couldn't replicate it (the standard response).

What mode are you using ? Auto or Manual ? If it's in Auto mode when the issue occurs, try switching over to manual mode

and set the fan speed manually and see if that changes it. Auto mode will run the fan speed at different speeds based

on the load sensors input to the HVAC system.  You need to test the system in manual mode before running to the dealer.

 

If you can duplicate the issue in manual mode, then you have a problem. Otherwise, it's working as designed.

Edited by drdiesel1
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What mode are you using ? Auto or Manual ? If it's in Auto mode when the issue occurs, try switching over to manual mode

and set the fan speed manually and see if that changes it. Auto mode will run the fan speed at different speeds based

on the load sensors input to the HVAC system. You need to test the system in manual mode before running to the dealer.

Thanks. Yep, I've tried both auto and manual and recirc and outside air. It's just randomly surging. Has been like this since day one in Jan 2013. At first I figured it was supposed to be like this, but I took it in and showed them but nothing happened. I may just try another dealer, but wanted to see if anyone with this issue had it resolved and what the resolution was.

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Thanks. Yep, I've tried both auto and manual and recirc and outside air. It's just randomly surging. Has been like this since day one in Jan 2013. At first I figured it was supposed to be like this, but I took it in and showed them but nothing happened. I may just try another dealer, but wanted to see if anyone with this issue had it resolved and what the resolution was.

I would check my 12V battery. If the battery is low, this could be a result of the system trying to charge it. Low 12V system

power will cause all kinds of problems. Do you have a 12V battery charger ? You'll need a way to check voltage and SOC

on the 12V battery to know what's happening.

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I would check my 12V battery. If the battery is low, this could be a result of the system trying to charge it. Low 12V system

power will cause all kinds of problems. Do you have a 12V battery charger ? You'll need a way to check voltage and SOC

on the 12V battery to know what's happening.

Thanks - Sorry, should have included some more info. I've been monitoring the 12v with my scangauge and seeing how the blower acts when other things are running (radio, lights, engine off/on, ice vs. hvb etc.). Also tried it without the cabin air filter but no change. Figure it's something to do with the blower motor, but not sure. I am one of those who had the 12v discharge issues, but that was fixed when I bought a new coolant pump and pigtail harness of my own and had Ford fit it for me, so that wasn't the issue.

Edit: Also bought a new 12v battery a few weeks after replacing the coolant pump, and am up to date on the multitude of recalls we've had. Just seems like the blower motor is bad.

Edited by kc1174
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Thanks - Sorry, should have included some more info. I've been monitoring the 12v with my scangauge and seeing how the blower acts when other things are running (radio, lights, engine off/on, ice vs. hvb etc.). Also tried it without the cabin air filter but no change. Figure it's something to do with the blower motor, but not sure. I am one of those who had the 12v discharge issues, but that was fixed when I bought a new coolant pump and pigtail harness of my own and had Ford fit it for me, so that wasn't the issue.

So you're saying even with the car not running (accessory mode) HVAC on with the fan set manually (by pushing the fan speed button) the fan motor still surges ? If so, I would have the dealer check it,,,,,if you can duplicate the problem for them to see it. Show the tech not the S/A.  The tech will be the one working on it, so it's best to have them see it for themselves.

Edited by drdiesel1
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Here's a systems overview of the HVAC control.  It wouldn't be very hard to find out what the actual

fault is as long as it can be duplicated while the tech has the vehicle in the shop. Some quick voltage

drop testing and monitoring will pinpoint the COF.

 

I put red dots to indicate the main players in this diagram for the HVAC system.

post-1464-0-81346000-1420398071_thumb.jpg

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Do this immediately. I stuck with one dealer while my warranty ran out. After the warranty was out, Ford basically told me that I was on my own even though the issues were pre-existing and I had documentation on it.

Sorry to hear that - I'm already onto dealer #3, after a tire rotation that didn't happen, and a 4 hours MFT update that they said they did and then Ford sync support told me the dealer didn't attempt. Fortunately I have a year or 21,000 miles to get it fixed and a 5/100k esp after that.

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Here's a systems overview of the HVAC control. It wouldn't be very hard to find out what the actual

fault is as long as it can be duplicated while the tech has the vehicle in the shop. Some quick voltage

drop testing and monitoring will pinpoint the COF.

 

I put red dots to indicate the main players in this diagram for the HVAC system.

Untitled-1.jpg

Cheers!

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Sorry to hear that - I'm already onto dealer #3, after a tire rotation that didn't happen, and a 4 hours MFT update that they said they did and then Ford sync support told me the dealer didn't attempt. Fortunately I have a year or 21,000 miles to get it fixed and a 5/100k esp after that.

 

Yeah, we have the extended warranty too, but it doesn't cover any of the interior crap that rattles and vibrates.  Nor the window squeaking, etc.  Suffice it to say, this will be my last Ford.

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  • 1 year later...

I know this thread is over a year old, but my 2015 C-Max just started to exhibit this behavior.  I can hear the fan on the AC fluctuate. It's like the whine noise goes up and down. You can defiantly hear it in the air flow if that makes sense. 

 

I'm confident it's not having to do with the temperature control.  

 

I'll bring it up on the next service but based on past comments, they won't find anything. 

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