The auto volume in my Corvette is based on speed and works fine. The same thing with my last Ecalsde. If the other GM vehicles have systems that work, how come the Hummer system doesn't. I have come to the conclusion that GM makes great powertrains but the rest of their vehicles leave something to be desired.

Mine does not work either.

All of my previous GM's w/auto-volume worked just fine as follows:

set the volume - increase the ambient noise in the cabin, volume automatically increases - - decrease the ambient noise in the cabin, volume automatically decreases.

Just my 2cents worth, I know what autovolume is and I have had it in other cars but the auto volume does not work in my H2 either and something else I noticed is when I press the button on the radio is says "AutoVol Off" so everytime I get in it is supposed to be on anyway!? Anyhow so i hit the button again and it SAYS it turns on but there is no difference in sound whatsoever. I tried with window down and sunroof open. Maybe a flaw in the system when the were mass produced??

I got a question. Does anybody's auto volume work? I am curious to know if this feature works at all in anyone's H2.

I tried it today for the first time, didn't work at all. The strange thing is that in my last 3 GM vehicles it worked very well. Sounds like some sort of disconnect to me. There must be some sort of sensor that detects the noise in the cabin. Does anyone have info on this? Maybe it just doesn't exist in the H2.

Maybe GM forgot to run the speed sense wire to the radio?

Well, the wiring diagram for 2003 H2 does not show a speed sense wire going to the radio. However, the 2004 wiring diagram does show it going to the radio.

So this info may answer your questions.

Karl
www.pac-audio.com