Al and Missy, I agree. However, adding the dedicated wires after the fact is not worth the trouble. One of our FantasticFans was installed by the dealer, and I installed the other one.
There is one advantage. We always air out our Bambi when we first arrive, to purge any carbon monoxide that has accumulated from towing.
Before we pull out of a campground, we close the FantasticFan lid (which turns it off) and turn the wall-mounted switch that controls the overhead light and FantasticFan to OFF. Then, we pre-set the fan to ON/OPEN, HIGH and OUT.
Then when we arrive, before entering our Bambi, we latch the door open, flip the wall switch to ON and let the FantasticFan run for a few minutes while we chock the wheels, and hook up the shore power cord and hoses. When we finally enter our Airstream, all of the exhaust fumes are gone.