Relay problem? (Clicking from behind fuse box.)

[stellar678]

So, my 3rd Gen has of course been having the normal problems with its stock bose radio. It turns on and off pretty much randomly, but it does seem to be "on" more often in (a) the summertime or (b) when the car has been driving for an hour or more. Kinda makes me think it has something to do with temperature...

Anyhoo, the real question I have is in regards to this clicking from behind the fuse box. Often (but not always) when the radio is changing states from off to on or vice versa, this clicking sound comes from behind the fuse box. It sounds kind of like a baseball card in the spokes of a bicycle wheel. I've had suggestions that it's a problem with some relay, but I figured if I came here I'd probably find some awesome constructive advice.

Any ideas? Thanks for whatever you can think of!