Hello Jeff,
The charger switches are usually part of a piece of equipment, so if you want a direct replacment, you need to contact the manufacturer of teh equipment or a dealer for that particular make of equipement.
Alternatively the caravan dealer that sold the caravan should be able to help.
It is possible a suitable switch may be availbale from the likes of Towsure, but without knowing the exact make and model of caravan/equiepemnt I cant say for sure.