Plug your RV in at home and then plug this into an outlet in your RV.

Easy peasy It will tell you exactly what is wrong if it's in your RV wiring. If the tester shows nothing wrong that it could have been the shore power.
You can pick these testers up at any box store for a couple of bucks. Has saved me a couple of times. After I hook up at a CG I plug it in over the stove so I know what is going on electrically at all times because things can change and this tester will show it.
I never leave my RV for electrical repair until "I" test it and know what the problem is first!