When does the Speed Volume Control kick in?

I know it's supposed to increase the radio volume the faster you drive or if it senses more wind, but mine never does this and I ride with the windows open like 90% of the time.

 

where do you have your settings at? When I use to have it, it usually kicks in at around 30mph. I would turn the settings all the way up and see if you notice a differnce. Try first with your windows up to make sure that the system works. Works well in my 97 SS when I had it and works awesome in my 02 Avalanche