hooking up parktronic behind bumper
 

i've had my 03 A8L for about a year, and the parktronic has never worked, just one long beep every time it's put into reverse. yesterday i pulled over a curb and caught the bumper, pulling it out of place. when i took a look at it to fix it, i noticed that there was an electrical connection behind the bumper that seems to be for the parktronic sensors. it's not plugged into anything. can anyone tell me where this thing plugs into? anyone happen to have a pic or a diagram. i can't find anything that it would/could/should "plug" into.

here's a couple of pics of what i'm talking about.

thanks folks!