This is probably a dumb question but Im going to ask it anyway. I just installed a hitch bike rack for my mountain bikes but the back up sensor keeps giving a warning and then slams on the brakes. Not ideal as I have the rack on year round. Tried to follow the manual to disable with no success. I read that if a 7 pin trailer plug is inserted it prevents the warnings. Maybe the final solution. I would appreciate any ideas or thoughts.