RV Repair: Electric hot water heater, hot water heater, electric hot water heater

Question
I have a hot water heater in a 1996 33' Wilderness travel trailer that runs off both electric and propane.  Last fall before I winterized it, it was running off the electric.  This spring, it would not function under electric power.  It seems to work fine with propane.  I have replaced the on/off electrical switch thinking that might be the problem, but still does not seem to be working on electric.  I'm not sure the switch is installed correctly.  Any suggestions?

Answer
Hi:
Either your electric heater coil is electrically open or there is no power to the coil. The heater coil is exactly the same as the heater coil in your home water heater. The coil screws into the rear of the tank most of the time. (I have seen them in the front). There are two leads going to the coil for 110V AC power. It is a fused (breakered) circuit. Take the wires off the coil and check the resistance in the coil by connecting an ohm-meter to the two coil leads. If you get a good reading, somewhere between 5 to 25 ohms the coils is good. Check the voltage to the two wires you took off the coil, carefully 110 volts AC tickles. If you have voltage there the coil is bad. If the coil resistance is good and the voltage is good the connection is bad. If the coil shows a huge resistance, in the meg ohms or 100000 ohms or better the coil is bad.  Thats about all I have. Good luck.
Bill