There are heavy duty modules available that can be spliced in if the OEM part is not available when the time comes that you want to do some towing. Some are powered from the battery rather than the tail light wiring.
http://www.drawtite.com/modulite1.htm
Note this one is compatible with Jeep which has the warning for the Jeep Grand Cherokee
"Do not connect trailer lighting system directly to the lighting system of your vehicle. Failure to comply could damage the vehicle electrical system and/or result in person injury."