When my original Dometic fan started making too much
noise, I replaced it with two Radio Shack muffin
fans.  Two must be better than one, no?  Then I noticed
that they ran much more than the original fan did.

I took them out and put in a replacement that matched
the original--Valterra fridge cool coil fan.  As everyone
else, I just used the fan, kept the original thermo-switch,
and didn't use the Valterra one.

The behavior of the fan/switch/fridge returned to normal.

My guess is that the two muffin fans made some kind of
interference with each other that resulted in less cooling.
Maybe one muffin fan would be better than two.

http://www.valterra.com/RV/refrigerator_fans.htm  I see now
that they think it is worth $41.56.  I sure don't think that
was the price 3-4 years ago!

Richard