>>3-I did those test in a 48hours period, never heard the fan in the back of
the fridge (I was not there all the time and it's still cold up here-65F)

Your cool ambient temperature is the most likely explanation.  The heating
coils in the back probably just haven't gotten hot enough to flip the
thermostat to turn the fan on yet because it's cool outside.  That happens
for me too at night, but during the daytime, here in New Mexico, where the
temperatures are now in the 90's or hotter, the fan runs all the time.

>>if the fan or thermo sensor is
dead, what is the consequence associate with that malfunctions. Is there
any danger or just a poorer fridge operation?

I think that it could permanently damage the heating/cooling unit to
consistently overheat.  Also, as you say, the fridge wouldn't cool well on a
hot day without the fan.

>>I guest
there is no easy way to test the fan (in the back) without removing the
fridge.

Right!

>>Should I remove the fridge too see if the fan is
working or the hell with that and just camping for the FIRST TIME THIS
SEASON!!

If it ain't broke, don't fix it!  I'd wait until a hot day and see if it
really doesn't work.  However, although it was quite challenging to remove
the fridge the first time, now I wouldn't hesitate to take it out again.
Pretty easy once you know how.

Good luck.
Paul