Well I have a 2008, so don't know if this helps if they arre already faded, but, I cleaned mine real good, then put turtle wax Ice car polish on them, seems to work really well, they haven't even hinted at starting to fade yet. This new turtle wax Ice is awesome, you can use it on everything on the truck, paint, glass and the plastic panels. Don't think I will be using anything else from now on, this stuff is like magic, and Sssoooo easy to use, no hard rubbing, put it on and wipe, that is about it.
http://www.icepolish.com/?tid=1949&gclid=CJv82KjCqZQCFQ4hnAod2FhlgA
Oh by the way, you don't have to get it online, Autozone, O'Reilly's and just about any place that has an automotive department has this stuff.