Electrical short to water heater

[lululand]

Hi I have a 92 landyacht. When I push the water heater button it blows fuse. Worked perfectly last season. Anyone have any suggestions?

thanks

[DaveFL]

Normally when a water heater element fails it is open, no electric flows and only have cold water no blown fuses.
I would disconnect wires from heater and see if it still blows fuse, might have a worn spot on wires touching metal.

[lululand]

disconnected the power to heater, this is a gas heated hot water so the switch in bathroom is only there to ignite the gas. As soon as I switch the heater on the fuse goes. It is very strange because the light in bathroom is connected to the same fuse and it works when I do not switch the heater on. I have a 15 amp fuse maybe it requires a 20 although I doubt that is the problem. Should I run a new wire from the fuse box to the bathroom and forget trying to find the short in the wire? Really need to figure this out. thanks

peter

[DaveFL]

Gas switch is designed so that the light only comes on for a short time, if the gas comes on, it go out. Does your gas come on and ignite? Should be able to hear besides getting hot water. Does the electric 120v heat the water?

[wasagachris]

Peter do not up size the 15 AMP fuse. The wiring is sized according to the fuse that protects it. If you up size the fuse you are running the risk of overloading the wire and melting it and possibly starting a fire.
It is not strange that the overhead bathroom light that is on the same circuit works until you turn on the switch for the water heater. The problem is obviously between the switch and the circuit board for the water heater. That wire will be the brown wire that is connected to the top terminal at the switch. The bottom terminal will be the 12 VDC + supply and the other two wires for the light will be a blue wire on the top terminal coming from the heater to the light and the bottom terminal wire will be a green wire for the 12 VDC- ground.
Disconnect the brown wire from the switch and disconnect the harness from the circuit board on the water heater and check if for continuity to ground with a meter. If that wire is the problem then replace it, if not disconnect the blue wire from the light and check it for continuity.
If neither wire is the problem I would suspect the circuit board. It will require testing by a qualified RV service center that has a board tester.

[lululand]

problem solved thanks to all. Yes it was the brown wire and my technician working on rv had the wire switched. it is now working perfectly.

peter