HVAC "is this normal" question...

[mrjulian416]

2021 GMC 2500-  First really cold day of the year around here.  I hop in, drive off, and once engine temp comes up, I crank the heat to HI, push the "floor only" button, and crank the fan knob to max.

 

There a huge whooshing/fan noise coming from right under the center of the dash, right below the dash organizer "tray".  It basically sounds like the defroster is blasting but it's not.  The air flow in the footwell is.... 'ok', but not like a blazing wind cooking my feet and rising up my legs.

 

When I put my hand down by the air outlets by the pedals, it feels like each of the openings is flowing freely, but.... are these fans/ducts just that loud? or is there a possible stuck mode door? or?

 

 

[BuckWallace]

Sorry, I can't answer your particular question, but it's really "who knows" with these trucks. I have a brand new 2024 3500, and any time the HVAC is on and I coast to a stop it sounds like a dirt bike is idling outside the truck. I can't tell if it's the blower motor or what...

 

Anyway, I wouldn't be surprised if your noise is considered "normal".

[Another JR]

I have a 2021 GMC 3500 hd SLT with buckets/“leather” and center console. When I push the floor air button and turn the fan all the way up the fan is fairly noisy but not really more than it is when going full blast in other configurations. A good amount of air is blowing in the footwells, but air is also blowing at a moderate level from the defroster vents. The ducting split between the floor and the windshield may be the reason for the noise you are hearing. 

[mrjulian416]

My only frame of reference is my '00 Sierra 1500.   Quiet, competent work from the blower/fan in any setting.  This thing sounds like the ducts are plugged and kinda feels like it too.  I was guessing it is "normal" and sounds like it might be.

 

Thanks for the input.

[Hoginedgewood]

I have a 22 custom, I don't like a bunch of noise, I rarely use HI. 
i have found you can never turn off defroster completely, I'm sure it's a safety thing.