94pt 'cool o matic' gally exhaust fan

[Gregory OConnor]

My center exhaust fan is a 12 volt roof mount exhaust. I keep it
running on a wall mounted thermostat(as designed) set at 90degF
with a window open and a cheap home style heater duct filter in the
window. works good, the filter gets choked with dust that would
otherwise settle in the parked bus or fan blades and motor(should
have a window open at each end but am too lazy).

I took the fan housing apart to clean and lube a noisy bearing and
uncovered a stowed three speed switch under the fan. the switch says
potentiometer and has two springs at back which I believe are heat
sinks (they get hot). I would like to have access to the switch to
reduce the speed while drycamping (layoff Leroy) and conserve
battery. I also like the idea of a slower moving fan while stored
and unattended and a higher speed fan while cooking.

I was thinking of hard wireing around the switch and moving the
potentiometer/switch to the wall near the thermostat . if you have
the switch where the fan mfg designed (thru a hole in the cover) you
cant slid in the headliner blank. Prob with moving the switch is
the "heat sink" in the wall???? I dont even know if the thermostat
has a wire 'to the fan' or 'to a relay - to the fan'??? also of
concern is the need for a heat sink?? does a product that produce
heat (pot switch),not consume energy?? would a rheostat be a better
choice for the wall??? gotta learn more about potentiometer vs
rheostat, both cool words but must be more to their differences.

Greg94ptCa