Humming noise behind radio/glove box

[Polishadrian]

Hello, first time poster here. 
 

Today my wives 2005 Lexus GX470 started making a weird humming, compressor like noise every time the car starts up. It happens whether I put the key in the ACC position or turn the car on completely. It goes for about 20-25 seconds and then stops. I turned the radio off and the air and the noise continues. I was hoping to see if anyone has ever dealt with anything similar and what they ended up replacing to solve the issue. Any help is greatly appreciated!!!

[ZekeInCBus]

I noticed the same thing today. I hope someone has good info. 

[RX400h]

The next time, open the hood before you start the engine. If there is a serpentine belt that is worn enough, a noise similar to what you describe may occur until the belt warms up.