It's the switch, mine did the same thing. New switch is about $20 +/-, I forget exactly, it was 2-3 years ago. Yep, Dealer only item too. When you get the new switch it comes in a clear plastic bag so you can see that there's this odd looking pin that sticks out of the switch - it's very tempting to mess around (pull it out/push it in) with this pin, but don't as it could ruin the switch. Of course once you open the bag you'll find a little instruction page that's folded (with the words facing each other) so you can't read it till you open the bag - that tells you to not mess with the pin.
Change out is simple - like Denny suggested remove the facia at the bottom of the steering column, makes things easy to see.