Ticking noise on 08 v-6

What the heck is the ticking noise coming from under the left side under the hood of my truck? I can hear it when idling and didnt think too much of it, but yesterday I did some low speed cruising with the windows down and I could hear it even more. It doesnt sound "normal" so to speak.

Should I be worried? It seems I read another thread a while back about this on someone else's truck.

 

You must have gotten the diesel.

 

It's the radio volume feedback controller - if you can hear it, the radio isn't loud enough.

(they all do it, there are some threads on making it quieter though, practise thy searchfu Grasshopper )