Mysterious sound on passenger side (short video)

[Lsxtrucker]

I've attached link to a video about 23 seconds long I recorded from inside the cab near my passenger side defrost vents near the windshield of my 03 Silverado. 

 

Edit: To clarify this sound was recorded with the fan off and air conditioning completely off. The truck is simply in the "on" position.  

 

I figured this would help with the diagnosis vs. me trying to explain the sound in words. At roughly 20 seconds in you'll hear the whine sound it makes every 30 seconds or so, on top of the odd grinding noise. 

 

 

Any help is appreciated. Thanks

[Lsxtrucker]

I'm really looking to figure this one out, i'd appreciate any help

[diyer2]

My guess is something fell down into the vent.

If you turn off the fan does it quit making noise?

If so the air moving is vibrating the object.

 

[Lsxtrucker]

1 hour ago, diyer2 said:

My guess is something fell down into the vent.

If you turn off the fan does it quit making noise?

If so the air moving is vibrating the object.

 

I should have clarified, that's the sound with the fan completely off...

 You can see why this annoying sound is driving me nuts. It makes this sound all the time. Only time it goes away is when the ignition is completely off. The sound comes on when the truck is in the on position without the engine running. (that's how I recorded this). Same for when the engine is running.

 

My air-conditioning, defroster and heat all work properly and the vents blow as they should. Any ideas?

[Lsxtrucker]

Anyone know this sound?

[diyer2]

I think the fan runs all the time when ignition is turned to acc. or run.

The only way to turn it off is to turn ign. off.

I still beleive something is in the duct work.

:)

 

[Lsxtrucker]

I don't think the fan runs when it's set to off regardless of key position but thanks for your input. The fan makes an entirely different sound. This is a slow electric motor noise which whines (like in the video towards the end) unusually. 

 

In addition the sound stays on with the HVAC and heat fuses pulled. 

[Lsxtrucker]

Will some folks have a listen and please offer input it seems to originate from below glove box

[Lsxtrucker]

Updafe: noise gets louder when recirculation is set on