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Changing HVAC Fan Speed?

rob_lewis

By rob_lewis
in Troubleshooting & Recalls

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rob_lewis New Member

rob_lewis

Posted
Posted

Just joined the board and tried to search for any mention of something similar, but couldn't find anything.

 

Just bought a base 2014 Sierra a month ago and have noticed that the fan speed seems to drop after a certain amount

of time. Looking in the manual, that would make sense for the Auto A/C option, but mine doesn't have it.

 

Whatever speed it's on, it will noticeably drop. Doesn't always do it, but finally did it with my wife in the truck, so I know I"m

not going crazy! :)

 

Anybody else notice this? Any way to override it? Changing the speed on the dial only changes it relative to the difference.

In other words, if the drop was 40% in speed on medium, when I crank it to high, it blows faster, but only 40% of what high

would normally be.

 

-Rob

Bowtiejunkie Enthusiast

Bowtiejunkie

Posted
Posted

Sounds like the same problem I have. Drives me nuts as you try to turn up blower speed and it won't increase to the prior level. Meanwhile the interior is HOT (in summer anyway) and the blower speed is limited. On my growing list of items for dealer to resolve.

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted

I understand that you are experiencing an issue when you change the HVAC fan speed, rob_lewis. Have you brought this up to your local dealership? I would be happy to look into this concern for you and reach out to your dealership on your behalf. Please contact me via private message if I can be of any assistance.

 

Jennifer T.

GM Customer Care

rob_lewis New Member

rob_lewis

Posted
  • Author
Posted

I have not brought it up to my dealer as of yet. I was trying to figure out if it's a feature of the system or if something was wrong with the system. The owners manual states that the fan speed will change when the target temperature is met, however, that's only on the automatic A/C systems, which mine does not have.

 

The other reason I haven't brought it to my dealer is I cannot reproduce it regularly. If I take it in right now and let them know that it occurs, they'll drive it for 5 minutes, say they can't reproduce it and give me the truck back. I am trying to figure out a way to make it happen on a repeatable basis so I can demonstrate it to a service person. Otherwise, taking it in would be a waste of time.

 

Now, if there's some known issue that the service department would be aware of, I can schedule something.

 

Hence, why I reached out to the forum to see if anyone else has experienced it before wasting time at the dealer for a "Well, it only happens sometimes and I can't tell you when it will happen"

 

-Rob

Silverado-Hareek Senior Enthusiast

Silverado-Hareek

Posted
Posted

You sure it's not entering an outside air cycle? While I haven't noticed this in my 2014, my 2007 Silverado would cycle to outside air every so often since I always kept it on inside air circulation which makes the AC and heat run better, but I guess for oxygen purposes it pulls in outside air (or switches to vent rather...whatever you want to call it) every so often and the system would noticeably decrease in fan power and cooling ability when this happens which is typical of a system in outside air/vent mode versus inside air re-circulation. Maybe this is what you're experiencing?

rob_lewis New Member

rob_lewis

Posted
  • Author
Posted

@Silverado-Hareek:

Might be a possibility. Handn't payed much attention to the exact condition it happens it, but will keep that in mind to check next time it does. Thanks for the idea!

 

-Rob

Silverado-Hareek Senior Enthusiast

Silverado-Hareek

Posted
Posted

@Silverado-Hareek:

Might be a possibility. Handn't payed much attention to the exact condition it happens it, but will keep that in mind to check next time it does. Thanks for the idea!

 

-Rob

 

You're welcome. One thing I need to add though. In my 2007, when it switched to outside vent the outside vent icon would illuminate. On the 2014, when I manually set it to inside circulation, that icon always stays lit until I change it and I have no idea if that means it is not doing any outside air cycles or if it is actually still doing them but keeps the inside circulation icon illuminated since that's the setting. I just haven't been able to play around with the system in the 2014 enough to figure out what it's doing and I haven't checked the manual yet either.

 

So I guess my personal status on this issue is "TBD." But I wanted to throw out my original observations anyway so you can keep that in mind when tracking down this issue.

Ianf Enthusiast

Ianf

Posted
Posted

My 2010 did this for about a year (Manual system with AC not the Dual zone). I checked all the wiring thinking maybe it was the ground or something not making good contact and found nothing out of the ordinary. Three weeks ago it just quit all together intermittently, and ran and slow speeds even when it did come on. Turned out to be a bad blower motor and I guess it had been going bad for about a year. The new one doesn't even slow down when stopped at a light idling at 500 rpm, so it was definitely the blower motor.

 

Easy to replace and cheap part easy to find. If its under warranty guess tell your dealer to look at it and describe the symptoms fully and they should get it right.

Fishingbear Enthusiast

Fishingbear

Posted
Posted

Mine does this too. I mentioned it to the dealer during an oil change and they looked into it but could not replicate the problem. It acts like it is in automatic mode when it's not. I've just learned to deal with it even though it's annoying.

rob_lewis New Member

rob_lewis

Posted
  • Author
Posted

Mine does this too. I mentioned it to the dealer during an oil change and they looked into it but could not replicate the problem. It acts like it is in automatic mode when it's not. I've just learned to deal with it even though it's annoying.

That's what I'm expecting, they won't be able to reproduce it. Glad to know I'm not crazy and that others have experienced it!!

 

Hopefully I can figure out a way to always make it happen.

 

-Rob

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted
Hi Fishingbear,

I see you’re also experiencing an issue with your HVAC fan speed. I’m sorry the dealer wasn’t able to duplicate the concern. I’d be happy to contact them on your behalf and look into this more for you. Just send me a private message if interested and we’ll discuss things further.
Regards,
Eddie A.
GM Customer Care
  • 4 weeks later...
wing98 Enthusiast

wing98

Posted
Posted

mine has done it a few times ,can get it to do it regularly enough to take it to dealer yet

I do need to make an appointment for a couple of small things i'll just add that in

I fixed my Bluetooth problems when I added the 8"screen and new hmi module

bladz1454 Enthusiast

bladz1454

Posted
Posted

Yea i have been noticing this since it got colder out. The actual temp is wacky too. 72* - 80* ALL feels the same and then at like 81* it feels correct, all the while the fan wont change speeds.

fondupot Senior Enthusiast

fondupot

Posted
Posted

I wonder if the regular HVAC (without Auto) still has a kind of automatic fan feature that turns the fan down once it gets to a certain temperature.

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