I have a 2004 Grand Cherokee Jeep that came with a trailer hitch and I have never towed before. I would like to start towing light weight trailers like 6x12's or U-Hauls one or two room trailers. Can anyone help me get started with this .... (the learning and who would I contact)? I know I need to get a BALL and I think I need to fiqure out the tongue weight or something