You are letting in a little cold air at your main power cord port. Take the inside access panel off to the main power cord storage area and snake a heavy duty extension cord through the outside port beside the main power cord. You can mount can possibly mount a plug and face plate on your access panel, depending on how it is configured. store the extension cord out of the way of the main cord when not in use so they will not get tangled up.
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler