If the plastic switch plunger has been damaged, you will probably have to buy a complete breakaway switch. If it is just the steel wire that is damaged, you can buy wire and crimp clamps at any hardware store. Or again, just buy a breakaway switch and use only the lanyard.
The wire should be longer than your safety chain, BUT hooked to the tow vehicle, NOT the safety chain. It should only operate if both the hitch and safety chain have failed. Ideally, it shouldn't even been hooked to any part of the hitch, but to some other point on the vehicle.
Texas Baptist Men-Retiree Builders member since '01
13 Silverado 3500HD D/A, 2wd CCSB srw, custom RKI bed
11 Cruiser CF32MK