'40 headlight switch

[russcc]

The headlight switch in the 40 is original, and seems to work ok except in the parking/taillight position the conductivity is not real good. Sure the contacts in the switch need to be cleaned. I would like to use something like CRC's Electroclean to spray into the switch. Any experiences Fodbarners could share on this. Also, does the knob, (original), come off or does the knob & shaft pull out as in some headlight switches. Thank you Fordbarners.