Water Heater Always On

Thanks for everyone's replies. While winterizing this past weekend I decided to cut off the plug to the water heater and install a new cord cap with the polarity reversed to make the black wire hot (120V) in the water heater. While doing this I pulled the covers to the element and thermostats and the switch out to check for any shorts to ground and to check for continuity to asssure the internal wiring for the heater was correct. One thing I found was that the wire that went from the plug to the water heater was not color coded but had a tracer molded into the wire to identify the nuetral so I guess that was an easy mistake to make during the construction of the trailer. Once I found there were no shorts and the heater was wired correctly I plugged in the new cord cap and the water heater worked as it should. I am definitley going to keep my eye on it but I know if it malfunctions again it should immediately trip the breaker or go out on the reset button. Thanks again.