Guys, I know what the floor dimmer switch is for, I even show it in use. Some tanks had it. The one which I had no idea was the far side of the steering wheel. Suggestion below posits a heater blower motor.
A change of pace. A little more comfort. Claimed to be one of three extant, this is available at RIA's auction 3-5 May 2019. Sold for $46,000
The Chieftain (Real name Nicholas Moran) is Wargaming America's resident tanker and amateur historian.