I use this thermometer for my fridge. It is left over from my motorhome. It has two temperature senders, one for the fridge, one for the freezer. Well, my Norcold 180 does not have a freezer, so now sensor #2 goes outside for the outside air temp. I probably bought it on Amazon, but I am sure there are more like it elsewhere. You can see that the remote sensor says #2, #1 is in the fridge, which is off. Also see it records max and min temps.
I wired mine to the running lights. I just turn on the lights and my Garmin camera mounted above the T@Bs license plate pops up on the GPS screen. No need for a switch.
Re: Frankly its unbelievable that NuCamp builds a quality camper but just doesn't make it work better...