How Rare? S83 1970 wheel

there was a service update for the wheel so it would not accidentally go off in the heat. It said to take the wheel apart and deepen the channel where the rimblow switch was. either file the plastic or score it so that the switch had room to expand.
I left my car home and went to the National's in the 90's and when I came home the harness had burned from the horn switch to the horns and killed the battery

will keep that in mind