Mechanical hum -- behind stereo head unit?

[minnesota]

??? wondering if anyone else notices some kind of light mechanical hum --- seems to come from behind the stereo head unit sporadically --- sometimes even after truck turned off. I've also had it kick in when listening at very low volume, truck off, key on Accesory. Any ideas what the #### it is? I could do without. This is in a C3, but I'd think the head unit is same as many other models have.

[Shaners]

I think there is a cooling fan back there for the head unit.  I think it is thermostatically controlled...

[minnesota]

Shaners - thanks -- was thinking that as well -- must be new feature for 99+ models. 97 Sub had essentially same unit but I never heard a fan...

[carguru]

Shaners is right.  There is a small fan in the back of the radio.

[Import Hater]

I too think it's a cooling fan in the radio.  I only hear it after I've been driving for a while and really had the volume cranked up.

 

Rob

[mikeb]

Good info guys I've been wondering what that sound was.

[woyster_00z71]

It is a cooling fan located on the back of the stereo unit.  My friend has a '96 chevy truck that we investigated the sound on.  Upon pulling the head unit we saw the fan mounted on the back.  When the stereo gets hot, it turns on regardless if the truck is on or off or what...kind of annoying.

 

But anyway, that is what it is.  Don't know what year they started putting them on but at least '96 for sure.

 

Just my 2 cents.

 

B.J.