CMC used cheap low amp universal headlight switches . "Speedway" sells a 30A universal switch that will work or you can buy a cheaper one but will need to run a relay. If, the PO used the CMC harness, the diagram is here in the SOC files but your harness may have been heavily modified as that harness was a mess out of the box. Best to sort out a single circuit at a time. When I resto a CMC my big scissors is the tool of choice to have a clean start using a Vintage Motorcars harness.