You didn't post what RV it is in or what type you have. Mine is go outside and manual light. But if you post your brand and size water heater maybe someone could help. On mine you have to hold down the pilot light button for some time to get gas to the pilot light.
2017 SLX 195RB
2014 Jeep Grand Cherokee Overland, gas 3.6 V6
Andersen WDH hitch
Dometic Milenco Aero mirrors