I haven't heard of one in a 1500.
However they didn't start putting them in until the new body style 07 or later. Not sure so either way you have to mess with a brake controller.
However if you get a Tekonsha Prodigy or P3 you can also get a harness. Plugs in under the dash and into the controller. Should have one fuse to plug in under the hood and mount the controler. That's it.
Here are some pics for you.