Since you already have a 6-way on the back of your 2001 Holiday Rambler Imperial it's possible there's already a brake circuit. However, since the previous owner was towing a vehicle it may not and you'll need to check for a wire running from the back of the 6-way to the cab of the RV. I've attached a diagram that may help you determine it. Traditionally, the brake control wire is blue and will connect to the back of the 6-way connector at the 3 O'clock position or center position, depending... view full answer...