Ok then, let's do some testing. First thing, when you turn the switch on for the hot water do you hear the clicking of the igniter? You may need to go out side to the hot water heater and have someone else turn the switch on because it will not click for long if it dose not light.
If it is clicking, dose the flame come on at all? Dose it come on at and goes off quickly or not come on at all?
If the flame comes on and goes off it may be the thermocouple, this is the cylinder thing that the flame heat up almost to red hot, this tells the solenoid the flame is on and stay open. If the thermocouple is not hitting the flame or is dirty bend it and clean it so it is in the flame.
If the igniter dose not click at all you need to check the power at the control module, that is the black box secured to the front of the tank and has wires coming out of it. There is sometimes a fuse on the module so if there is check it. If not use you tester and check for power to the module, if you have none then you need to find out why, look for fuses in your house 12vdc fuse panel. If you have power on the module and not clicking of the igniter you have a bad module. This is not uncommon at all and you can get a new one at any good RV store. Modules go bad often.
If you have power to the module and clicking on the igniter then put your tester on the gas solenoid and see if you are getting power there. If you are getting power and no gas is going through then bad solenoid.
1953, most likely it is going to be the module, but do the testing to be sure. I will be here all day tomorrow so please let me know what happened, Also if you need more help or something else to test.
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