That metal strip in the middle is bi-metalic and was designed as a protection device on the original trucks. When it over currents, the strip heats up and breaks the circuit. When it cools in a few seconds it closes the circuit and the cycle repeats.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
