Auto climate fan speed dropping after startup

[tootall87]

2023 GMC AT4. It's hot outside, I get in the truck and start it. Auto climate control fan speed takes over and starts blowing full blast. Good. Here's where it gets weird. There's a half second pause in the radio and then the fan speed drops to a minimum. Move the auto climate temp knob, nothing happens. I have to go to manual climate control then back to auto or cycle the end call/mute button twice to get the fan speed back up. This happens twice on every start up. Very frustrating. Has anyone else had this issue? I thought maybe it was just my truck but I had a rental Suburban this week and it does the same thing. It's almost like the truck drops the fan speed to reduce the noise so the microphone can hear me better. But I initiate no action to need the microphone. Hopefully have time to go to the dealer in the next few weeks.

[eppieguy]

Unfortunately normal, waiting on a fix from GM, there is another thread around here about it. Quick trick is to hit the mute button for a couple of seconds and then unmute it and it seems to go back to normal.

 

[tootall87]

3 minutes ago, eppieguy said:

Unfortunately normal, waiting on a fix from GM, there is another thread around here about it. Quick trick is to hit the mute button for a couple of seconds and then unmute it and it seems to go back to normal.

 

 

That is incredibly frustrating on a high end truck. Grrrrrr. Any idea on a service bulletin number or something like that to present when I go to the dealer?

[eppieguy]

9 minutes ago, tootall87 said:

 

That is incredibly frustrating on a high end truck. Grrrrrr. Any idea on a service bulletin number or something like that to present when I go to the dealer?

No, Sorry, I haven't seen anything posted about that, it happened after the last over the air update.

[repairman54]

Go into the auto settings, there is a fan speed setting for auto. 

[jaxcam02]

I never had this issue until the dealer installed updates last week

 

[GMCustomerService]

On 8/17/2023 at 1:19 PM, tootall87 said:

2023 GMC AT4. It's hot outside, I get in the truck and start it. Auto climate control fan speed takes over and starts blowing full blast. Good. Here's where it gets weird. There's a half second pause in the radio and then the fan speed drops to a minimum. Move the auto climate temp knob, nothing happens. I have to go to manual climate control then back to auto or cycle the end call/mute button twice to get the fan speed back up. This happens twice on every start up. Very frustrating. Has anyone else had this issue? I thought maybe it was just my truck but I had a rental Suburban this week and it does the same thing. It's almost like the truck drops the fan speed to reduce the noise so the microphone can hear me better. But I initiate no action to need the microphone. Hopefully have time to go to the dealer in the next few weeks.

This is certainly not what we like to hear, tootall87.  Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your the auto climate fan speed on your 2023 GMC Sierra AT4. To do so, please send an email to [email protected] with ATTN: tootall87/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
 
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
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[borstar1]

Ever find a fix for this? I just bought a 23 at4 a few weeks ago and mine does the same thing.  

[jaxcam02]

10 hours ago, borstar1 said:

Ever find a fix for this? I just bought a 23 at4 a few weeks ago and mine does the same thing.  

I just dropped off my truck at the dealer for a number of items. This being one of them. The only thing that is going to get GM to fix the issue is for people to leave their trucks at dealers and force them to pay out for warranty issues.

[redwngr]

On 8/23/2023 at 2:18 PM, jaxcam02 said:

I never had this issue until the dealer installed updates last week

 

Some updates returned settings to defaults.

[GMCustomerService]

14 hours ago, borstar1 said:

Ever find a fix for this? I just bought a 23 at4 a few weeks ago and mine does the same thing.  

This is certainly not what we like to hear, borstar1.  Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with the Auto Climate fan speed on your 2023 GMC Sierra AT4. To do so, please send an email to [email protected] with ATTN: borstar1/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.
 
Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
www.gm.com
 

[jaxcam02]

5 hours ago, redwngr said:

Some updates returned settings to defaults.

been through the updates and re adjusted my settings and still getting the same behaviors with the fan speed adjusting on its own. 

[MJC815]

Same issue with my 2023 1500 SLT.. only resolve is to press call/then hang up buttons. Returns the AUTO fan to high. Ive talked to my dealer - they arent even aware of the issue and do not have a fix. Has anyone had any luck with eliminating this issue?

 

I have tried to narrow it down and can only think 

 

When I start the truck -the fan correctly comes on high (in settings - auto fan speed)

then after a few seconds - reduces speed - I think its the time it takes for the phone to connect and for some reason - the phone connecting makes the computer think it is making a call and thereby reducing the fan motor as it does when I make calls - ugh!!

Expen$ive truck and I have to manipulate for the fan motor to blow properly??? COMEON MAN!!

[newdude]

44 minutes ago, MJC815 said:

Same issue with my 2023 1500 SLT.. only resolve is to press call/then hang up buttons. Returns the AUTO fan to high. Ive talked to my dealer - they arent even aware of the issue and do not have a fix. Has anyone had any luck with eliminating this issue?

 

I have tried to narrow it down and can only think 

 

When I start the truck -the fan correctly comes on high (in settings - auto fan speed)

then after a few seconds - reduces speed - I think its the time it takes for the phone to connect and for some reason - the phone connecting makes the computer think it is making a call and thereby reducing the fan motor as it does when I make calls - ugh!!

Expen$ive truck and I have to manipulate for the fan motor to blow properly??? COMEON MAN!!

 

 

Have your radio updated.  Have them pull up 24-NA-100: Radio Software Version Y172 – Multiple Updates for IOK - (Jun 11, 2024).

 

One of the things it fixes:  

 

HVAC:

• The blower speed turns down at startup by itself

[MJC815]

is that a dealer update or just "software update" I can do in my vehicle??