Five wire surge lockout not working. I can't back it up the drive without putting that tabbed key in to manually lock out the surge. The fifth wire on a five flat is supposedly the rear back up lights that engages a solenoid to prevent brakes from engaging when in reverse.
I have used all three of my trucks to pull it at one time or another and same deal. Wires in good shape and Extreme trailer only a few years old. Could be a bad solenoid already?