what the hay is this thing?!?!?
 

ok, i know im gonna be called a noob or squid, but i have this knob that is located below my radio that spins about one whole turn. It is about as big around as a tootie roll and about 3/4" long. it is below my climate controls where the paneling curves out and away from the driver. it doesnt do ANYTHING. should it? what is it? it seems to be OEM. but i cant figure it out. what is it?

Year of truck and picture would help. Based on my trucks it doesn't sound OEM but need to see it.

Did you buy your HUMMER used? If so I believe someone had an aftermarket amp mounted in the vehicle for a subwoofer. It is prob. a bass control knob that they didn't remove because it would have left a hole.

That's my guess until I can see it in a photo?

that is exactly what I was thnking. After I posted that thread, i kept thinking about it and was pretty certain that it might have to do with that. Yes it was purchased used and there was a system in it at some point. all the wiring is run, pretty neatly I might add, and there is some serious 10gauge wire with all the other hook ups under the right rear seat. Its been a while since i messed with a system. And all my amps had bass control on the amp only Thanks for the help!