2021 GMC AT4 Ventilated Seats not working

[Jeremy Lawrence]

The ventilated seats, both driver and passenger don’t blow cold air. The blue lights come on when turning them on but no cool air from the seats. The seat heaters work fine. Any suggestions?  Trying to keep from having to take the truck in to the dealership. 

[cltsig]

Do you hear any noise when you turn them on?  With my 2020 AT4 you definitely hear them.  Likely the dealer will have to fix it either way but since it is both seats, likely something "upstream" of connectors on the seats.  My .02.

[Liquid Plumber AT4]

17 minutes ago, Jeremy Lawrence said:

The ventilated seats, both driver and passenger don’t blow cold air. The blue lights come on when turning them on but no cool air from the seats. The seat heaters work fine. Any suggestions?  Trying to keep from having to take the truck in to the dealership. 

Is it blowing any air at all when the button is on?? I have the same exact truck and noticed the same thing on hot days or if had windows open.....i figured out when the ac was on it blew cold air. I think it takes the ac cold air from the vent under the seat to blow cold air. Try that and post back to see if that worked

[Kanon Morris]

Like already mentioned, the vented seats blow air, not necessarily cold air.  If the air in the cab’s cool, they’ll blow cool air.  If it’s warm…. Well

[gmtech2014]

Each vented seat consists of 2 blower motors; one in the seat back and one in the seat cushion. During vented seat operation, the vented seat blower motors move cabin air through channels in the foam pad and small holes in the seat covers causing a cooling effect to the occupant.

With the ignition ON, battery voltage from the ignition main relay is applied through a 15 A fuse located in the Instrument Panel Fuse Block to the seat cushion blower motors. Ground for each blower motor is provided through separate ground circuits and a common ground connection.

When the seat heating control module receives a ventilation seat command, it sends a low side drive pulse width modulation (PWM) signal through the blower motor control circuit to the seat cushion blower motor indicating the seat ventilation command. The logic in the blower motors sets the blower speed to the switch set point. The blower motors run causing a cooling effect to the occupant.

 This is From GM service information and the description and operation 

[Jeremy Lawrence]

Nothing. No sound, no air. Just checked my girlfriends GMC Sierra and you can hear the air in her seats when they are on. Is there a connection or fuse I can check?  

[Jeremy Lawrence]

2 hours ago, gmtech2014 said:

Each vented seat consists of 2 blower motors; one in the seat back and one in the seat cushion. During vented seat operation, the vented seat blower motors move cabin air through channels in the foam pad and small holes in the seat covers causing a cooling effect to the occupant.

With the ignition ON, battery voltage from the ignition main relay is applied through a 15 A fuse located in the Instrument Panel Fuse Block to the seat cushion blower motors. Ground for each blower motor is provided through separate ground circuits and a common ground connection.

When the seat heating control module receives a ventilation seat command, it sends a low side drive pulse width modulation (PWM) signal through the blower motor control circuit to the seat cushion blower motor indicating the seat ventilation command. The logic in the blower motors sets the blower speed to the switch set point. The blower motors run causing a cooling effect to the occupant.

 This is From GM service information and the description and operation 

Thanks...I'll give the fuse box a look first.

[imartinez92]

Any update? My 2020 sierra is doing the same. No air is blowing through the seats but seat warmers are working 

[Time2gofishing1980]

I’m pretty certain that suck air down through the seat, not blow up up. 

[Jeremy Lawrence]

I sold that truck.  That thing had one problem after another. I did find that my passenger side worked but as soon as I turned on the driver side the passenger side stopped. GMC looked into the issue and replaced the module that controls it, but that didn’t fix it. They wanted more time to check all the wiring but they had my truck for two weeks already due to a cylinder misfiring. Took them more time to find parts to fix it than it did to replace the bad parts. This truck was full of computer and electrical issues. Sure hope newer models aren’t as bad.