You should be able to drop a cover on the lower center dash to get to the brake switch wire. It's way up there, but you should be able to get it. Then, under the hood stuffed between the firewall and the wheel well should be an orange and blue wire for the electric brakes. I don't think there's anywhere else convenient to get the brake switch. I'm not sure if a wiring harness exists to plug into the junction box to get all the wiring for a brake controller.