What year is your LX--I want to say the last one I drove was a 2005 and there was not a switch. Could be a lot of things, but if you're sure there isn't (and wasn't in the past) any equipment added, the mostly likely use (IMO) would be a kill switch.
Aaron, you can pull the center console up pretty easily and follow it. I had something similar in my LC. I reached up behind the lower dash and pulled down the FM transmitter for the aftermarket DVD system.