2005 Yukon. Fan in the roof between the 2nd and 3rd row seats

[dan bond]

this is a 05 Yukon xl 1500 with rear air. when i turn on the key there is either a motor or a fan in the roof that starts running and i can not figure out how to turn it off. it runs from the time you turn on the key till you turn off the key and then you hear it winding down and stops. i even have the control in the dash out to have new leds installed. when i turn on the ac with the roof control you can hear the blower kick on and the speed go up or down as it should so this is not the blower. it sounds like it is above the two round vents in the roof between the (2nd and 3rd) rear seats. thanks for any help

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I know that there are fan(s) in the headliner that serve a specific purpose. I cannot personally assist you with the specifics of your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

@Doubeleive

 

[Fless]

Sounds like it might be one of the temp sensors for the AUTO HVAC system. You're able to set a numerical temperature on your HVAC head unit, right?

 

[Doubeleive]

this is a 05 Yukon xl 1500 with rear air. when i turn on the key there is either a motor or a fan in the roof that starts running and i can not figure out how to turn it off. it runs from the time you turn on the key till you turn off the key and then you hear it winding down and stops. i even have the control in the dash out to have new leds installed. when i turn on the ac with the roof control you can hear the blower kick on and the speed go up or down as it should so this is not the blower. it sounds like it is above the two round vents in the roof between the (2nd and 3rd) rear seats. thanks for any help

there is a interior air temp sensor, right above the drivers head and some have one in the second row on the passenger side.
it should be whisper quiet and unable to hear it unless you have superman ears
so if it is noisy it probably needs to be replaced they about $35-40 online

More Information for GM GENUINE 22834330

 

[Joseph Garcia]

there is a interior air temp sensor, right above the drivers head and some have one in the second row on the passenger side.
it should be whisper quiet and unable to hear it unless you have superman ears
so if it is noisy it probably needs to be replaced they about $35-40 online

More Information for GM GENUINE 22834330

Thank you, Wes.

 

[Roilux]

there is a interior air temp sensor, right above the drivers head and some have one in the second row on the passenger side.
it should be whisper quiet and unable to hear it unless you have superman ears
so if it is noisy it probably needs to be replaced they about $35-40 online

More Information for GM GENUINE 22834330

Co-signed. Definitely replace the aspirator with a Genuine GM part. I went aftermarket the first time and ended up replacing both units in less than a year.

 

[Roilux]

this is a 05 Yukon xl 1500 with rear air. when i turn on the key there is either a motor or a fan in the roof that starts running and i can not figure out how to turn it off. it runs from the time you turn on the key till you turn off the key and then you hear it winding down and stops. i even have the control in the dash out to have new leds installed. when i turn on the ac with the roof control you can hear the blower kick on and the speed go up or down as it should so this is not the blower. it sounds like it is above the two round vents in the roof between the (2nd and 3rd) rear seats. thanks for any help.

Should you tackle replacing the aspirators yourself, here's a preview of what to expect in this post. Refer to earlier posts in the thread for the front unit. (Wonky link - scroll up a few posts once the page loads.)

Mircophones in roof of Denali making a Humming noise

I just picked up my new to me 2005 Tahoe this morning and discovered the rear one on mine was buzzing. Merely blowing out the built up dust didnt fix mine. They ARE serviceable for anyone handy enough or inclined to give it 20 minutes of your time. The hardest part was coming to the eventual...

www.tahoeyukonforum.com

I'd expect you'll run into a couple more fasteners with the XL's longer headliner.

 

[Gabefo]

this is a 05 Yukon xl 1500 with rear air. when i turn on the key there is either a motor or a fan in the roof that starts running and i can not figure out how to turn it off. it runs from the time you turn on the key till you turn off the key and then you hear it winding down and stops. i even have the control in the dash out to have new leds installed. when i turn on the ac with the roof control you can hear the blower kick on and the speed go up or down as it should so this is not the blower. it sounds like it is above the two round vents in the roof between the (2nd and 3rd) rear seats. thanks for any help

Hi there. I have the same truck and had the same problem about 10 years ago. There is a small fan sensor in the headliner between the second and third row seats. It is designed to pull air in and across a thermistor which then controls your rear climate control for heat or AC. You cannot turn the fan/sensor off. The fan is worn out and needs replacing. I suggest replacing the sensor if you like climate control. If you don't, then just unplug it. The problem is that it is located in the headliner so you will need to remove some of the side panel trim. It's not impossible, but you probably need about 2 hours of work.

If you are going through the trouble of unplugging it, I would just replace it while you are there.

Good luck and write back if you need help.