I have a 2004 Ford Expedition and I'm wondering if anyone has the same problem I am having when hooking up my trailer brake controller. There are 4 wires coming out of the brake controller and there are 5 wires (all marked) coming from the wiring harness provided with the Expedition along with a schematic, a 30 amp fuse and some sort of relay switch. I hooked up the 4 wires from the brake controller to the 4 wires (out of the 5) to the wiring harness. I then plugged in the harness to the piece under the dashboard. Based on the schematic, I installed the 30 amp fuse and the relay. I have gone over it and over it again, and it seems like everything is connected and installed the way it's supposed to be. However, the trailer brake is not being engaged when I press on the brake or when I use the manual brake on the controller itself. There is no connection for some reason. So using a Voltmeter, I checked to see if there is voltage coming from the pin in the seven-pin connector when I apply the brake or the manual brake, and there is nothing. Like I said, I have gone over it and over it, and it seems like everything is connected correctly. Am I missing something?

 

I'm lost on this one. Can't you plug and play this without doing any wiring? Just plug the Primus into the receptacle in your Expedition using the adapter pig tail between your controller and your truck.