We have a 2000 Ford Windstar. Brakes installed by previous owner...I believe there is a short somewhere in the trailer lights. The car's brake lights are stuck on, which is draining the battery and making driving unsafe. At first I could get the brake lights to turn off by wiggling the box used to adjust the tension on the trailer brakes, but now that doesn't even help. Can I simply cut the wires, or is the trailer brake system tied into the main car brake system?