I have a different model N-L. On mine, there are two vent holes under the bench seats that are connected to the water and electric tunnel. Some heat is suppose to get to the pump area thru that tunnel. I did permanently disconnect and drain the outside shower lines.
Last year there was a discussion on N-L forum
Click Me for N-L forum about this same subject. Comments were made on how some insulated their pump compartment. Either look over the past treads on the N-L site or ask the forum members to help you find that thread. I don't camp in areas below 25F so I am not worried.
LeRoy
