A tow ball weight scale for a caravan, boat or work trailer is the only way to keep your tow ball weight constant and to help prevent sway.
As a result of running a cable across the axle, the first magnet will lock during braking, In addition, the magnet across the axle will not lock. Learn the secrets and taboos of caravan and trailer electric brake magnets. For many years, expert Auto Electricians and Manufacturers ran magnet cables across axles. The industry believed this was the correct procedure.