I bought a 2006 dodge dakota and it has the tow haul pkg. but there is no wiring harness for a trailer and can not find where to hook up a wiring harness yo the factory wiring any sugg.

There has to be one somewhere if it's a tow pkg... but if you don't see one under the rear bumper or where the spare tire should be or at least wires running to that area then you should take it to the dealership you got it from and talk to them about it... a previous owner may have removed the wires for some reason and if you have a warranty on it then it should be covered