Maybe trucks that have A/C have an "off" position on the slider lever--but every truck I have owned without A/C (73-87) has the fan running when the blower speed switch is all the way down (and says "OFF" on some trucks,even though its NOT !--its on "low" speed in the lowest setting...moving the heat/defrost or hot/cold lever wont shut the fan off,as they are not connected to any wires,only the air flow doors in the heater box..
I disliked having cold air blowing on me from the first moment too,so I tracked down the "low" speed wire at the blower housing and snipped it!..my heater motor had a nasty habit of running silently for about 4 minutes,then suddenly start to screech like a spun rod bearing until it warmed up,and I got sick of thinking my motor was about to seize up...I drilled a tiny hole in the rear bushing of the heater blower motor so I could squirt some oil in it every fall to keep it rom squealing too,on the higher speeds..