water heater 120 switch

Noticed that the lighted switch for the water heater has a dim flickering light. I can turn the switch to the on position and it glows bright. The camper is plugged into a 110 15 amp wall socket would this cause this to have this effect on the light in the switch. I am not using the camper just got it plugged in to keep the battery charged and run the ref. until I get ready for winter. Oh ya I have the switch at the water heater turned off.

I've seen this several times before. Go to an electrical supply house and buy a new 120 VAC toggle switch that is lighted. Your switch has bit the dust. Actually, the lit portion of it has taken a powder, the on/off still works. You can also order it thru a RV place and pay more because it is "RV APPROVED"...

Did you check to make sure the receptical is wired right and if it is grounded??