The heater blower motor on my 1962 Starfire with the Deluxe (non-AC) Heater has only one fan speed, low. The Blower Resistor is good. I believe there is a "master blower switch" which also controls fan speed. Is that switch located on the dash mounted heater control assembly? If so, must the entire assembly be removed from the dash for replacement? If removal is necessary, any suggestions on accomplishing such a project?