How many of us are there? Owners of Dodge based RV's?

Maya,

12.4 volts is 25% discharged. It also means that your converter is not charging your house battery. Now we need to figure out why.

Do you have a converter? If so, what make and model?

Take out the bulb of a 12v interior light. Turn on the socket and measure the voltage. If it is more than 12.4v then the converter is powering the interior 12vdc circuits. If it is only 12.4v then they are being powered by the battery and the converter is either not connected, not working, or you don't have a converter.