In the past, most people who ordered our type vehicles did not pay the $200.00 option to have an integrated trailer brake control unit installed at the time the vehicle was manufactured, but a lot of people did pay to get the heavy-duty trailering package and trailering receiver/connector option, which included a 7-pin round trailer connector at the back of the vehicle. That integrated trailer brake control unit comes in useful for trailers, for example, that have electric brakes rather than surge brakes, and the DIC (Driver Information Center) display on a vehicle was used to set options for the integrated trailer brake control unit.
Most of our vehicles (Tahoes, Yukons, etc.) have four loose, unused wires stuffed just under the steering wheel area that aren't used at the time the vehicle is manufactured because no one wanted the $200.00 option to have an integrated trailer brake control unit installed. However, times change, and trailers with electric brakes are becoming very common nowadays. The vehicle owner then needs an electronic brake control unit installed to use those electric brakes properly. norcal_mike, those four wires are no doubt the electronic brake control wires, which someone pulled out from just under the steering wheel area at some time in the past to wire into an aftermarket electronic brake control unit such as a Tekonsha 90195 P3 Electronic Brake Control unit. If you look closely, you will probably see a solid white wire, a blue with white tracer wire, a red with black tracer wire, and a solid blue wire. Those wires have been spliced into the appropriate wires (a solid white wire, a solid red wire, a solid black wire, and a solid blue wire, in all probability) of an aftermarket electronic brake control unit. The plug in your picture inserts into the aftermarket electronic brake control unit.
An aftermarket electronic brake control unit is the only option once one of our vehicles leaves the factory. They work very well. but they don't work with the DIC display.
Now, how come I know so much about this? Because I just installed an integrated trailer brake control unit today to work with a trailer I have ordered that has electric brakes. My boat trailer uses surge brakes, and I never dreamed I would have any use for that $200.00 option to have an integrated trailer brake control unit installed by Chevrolet when I ordered my 2010 Tahoe.
You can easily push the wires back up to get them out of sight, and then use some thick tie-wraps to hold everything in place so nothing moves around.