What you can do is add the wires as described above and run them to a switch under the dash. If your headlight switch is good, leave the under-dash switch off. If/when it melts, flip the switch to close the jumper and you'll have lights again. Alternately, put pigtail wires with blade terminals on the parking and low beam wires behind the headlights. If the switch melts, plug them in to jump them and continue driving.