I read an RVers site online who made a baffle to direct air into the
outside grille of the fridge so air can be grabbed while the RV is
moving forward,  and forced across the condensor fins/tubes for more
efficient cooling of the Fridge.  I have a small 12 vdc fan for the
condensor but i never thought it was capable of overcoming the air which
is going past the grille when travelling at highway speeds. So, being in
the hvac business, i neatly fabricated a sheetmetal box measuring 6"
high by 7.25" long by 2" deep from the exterior wall of the RV.  It
takes up one half the size of the grille so the remaining half can still
be used to exhaust the air out.  The box is exactly the same height as
the grille, so, it appears factory looking and blends in nice .  Coming
out of the back of the box, i have a short 3.5" length of 6" oval pipe
which terminates about a half inch in front of the condensor. I drilled
a small 1/4" hole on the bottom side of the box to let any rainwater out
that may collect inside. Taking the RV for a ride with the fridge on, it
appears the fridge cools down much quicker now while moving. Id imagine
that at speeds over 25 mph, there is alot of air being blown across the
condensor .  Wish i had a digital camera to post a few pics of it.
Anyways, just thought id share my experience. Maybe some of you have
already thought about it, or, maybe your rig came with an air intake on
that picks up air as your moving.  (??)