I just bought a 05 f250. On the dash if you open the square thing that contains the power point there is a four wire harness that plugs into nothing what is this. I will take a pic and post it if is not understood. Thanks

 

It might be the firewall pass-through wires. On the later trucks they started installing some wires that are taped off under the hood and under the dash for any purpose you wish, so you would not have to poke any new holes through the firewall.

If they are just cut off with no plug, I bet if you hunt around under the hood you can find the other ends. If they have a plug on the end, they are for something else like a trailer brake controller.