[Ganglin]

You can get one for about $35. Go to a truck parts place and tell them you need an engine heater outlet cover. You'll see them on trucks below the drivers door. They sell the power inlet insert as a separate item.

In our case I got one to add an outlet to the trailer exterior. Just bought the cover - then a large round extension cord replacement plug from Lowes - it slides right in to the cover. Someday it will get installed.