My 46 GMC had 2 switches for a deluxe heater with 2 separate fans, one labeled 'heat' for air to the floor, one labeled 'def' for air to the defrost tubes only [don't recall how many positions each had]
Bill
red58,
Looks like the 'def' switch was a 2 speeder.
1929-57 Master Parts Cat. Group # 9.779 DEFROSTER PARTS, Windshield
47-48 ALL ...SWITCH ASSY.,(high and low) part #3120407
ebay NOS 1947-1948 CHEVROLET DASH DEFROSTER UNIT #986132....... For car
ebay GM NOS DEFROSTER SWITCH
