Cold start trunk buzzing noise

[FeGee3]

Just the other day it happened the first time, and has happened twice more since. I am getting an electronic/metallic buzzing sound when I start the vehicle after it has sat for several hours. The buzzing sounds electronic and will only last at most 10 seconds before it goes away completely. It will not come back on again during the ride, until possibly the next cold start. From the drivers seat my best guesstimate is the sound is coming from the mid/rear of the trunk on the passenger side. Above the exhaust maybe.

I have not been able to grab a sound snip or video of the sound because it goes away quickly and has been unpredictable when it occurs, ie- it will not happen during every cold start. The temperatures have dropped in the Northeast, but I am at a loss here with this noise. Anyone experience something similar or can point me in a good direction? I have a 2021 S AWD.

 

[FeGee3]

Can anyone please tell me what is behind this vent in the trunk? I have determined the sound to be emanating from behind the trim/vent.

 

[Superdavest]

From what I could see the A/C evaporator core is there. Part # 97900 S9000

 

[FeGee3]

From what I could see the A/C evaporator core is there. Part # 97900 S9000

It is indeed, was able to get a light in there and see the numbers through the vent openings. Will have my Telly in to have it serviced on the 29th, can update afterwards.

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[FeGee3]

For anyone who may encounter this issue in the future: the buzzing noise was diagnosed by Nucar Kia in Tilton NH to be the rear AC heater vent actuator motor. They seemed familiar with the noise and problem, whether from other Tellurides or other vehicles they did not say.

The repair was completed at no cost to me as the vehicle is at 41k miles and about 2 years of original ownership. The part was available quickly, luckily, as the noise was an annoyance albeit for only 10 seconds at a time.