12 Volt Electrical issue?

I'd check voltage at your house batteries, battery disconnect switch, and battery cable connections.

Fuse! How did you check them? Unless you used a volt meter just looking is of no use.

Kevin
You need to tell us the make model year so we have an idea of what you have that may be unique.
What you are saying is that the RV works with 120 Volts ,
The Furnace and control panel use 12 V DC , so you are missing that
First check the battery voltage with no shore power, and then plug in and recheck.

Kevin,

Your problem is in the DC distribution.
Without knowing who made that panel, no meaningful information can be provided.

With no information about the age and manufacturer of the vehicle, nobody can do more than make wild guesses.

This is the sort of thing I used to frequently diagnose remotely before the depression. But, I knew what the owners equipment was (I still keep notebooks about the boats) and I knew each hard a meter to work with (because it came from me along with the first invoice).

Matt

My best guess is that your house battery(s) are dead. When plugged into shore power or on generator, the converter will provide 12v; hence, everything works.

First things first. Check your house battery(s) voltage. If below 12.2. they are considered dead and need recharging. If much below 12v, you may need new battery(s).

If batteries are dead, plug into shore power and check again. If still dead then your converter is not providing charging power to them. If the battery(s) go up to over 13 volts, then they are being charged.

So do this first and let us know the results......along with other info requested above.

Hope this helps

Ron

There is probably a fuse or circuit breaker between the battery and the converter. I would check that that is good. Knowing the battery voltage, when the RV is not plugged in, would be a big help.

Since no one else mentioned it, check to see if you have a battery disconnect switch that is activated.

Your house batteries are charged by a "converter" that converts 120volts AC to 12-15 volts dc to power your 12 volt dc devices and to charge your house batteries when you are plugged into 120volt "shore power". Charging power goes to your house batteries through heavy guage wires that connect to your converter Make sure that the wire connections at your converter are connected securely. Use the proper size allen wrench to tighten the connectors onto the wires. When plugged into shore power, measure the DC voltage at the house battery terminals, it should read over 13 volts if your converter is working and charging the batteries and the house battery disconnect switch and relay are working and there are no fuses blown in the house battery charging circuit.You will need to have a simple multi-meter and now how to use it to check voltages. If this is all Greek to you, take it to a trusted RV repair service for diagnosis and watch what they do. If it turns out that you need a new converter the Progressive Dynamics PD9245 is a good and popular choice. You may need new house batteries. I bought US brand batteries recently, they are considered as good as common Trojan brand but much cheaper. RV batteries are only good for about 10 years useful life if kept charged and proper electrolyte levels are maintained and your charger does not overcharge batteries
Learning about 12 volt systems and how to troubleshoot and maintain them in an RV is essential to pleasurable motorhoming.

I would like to Thank everyone that has responded so far. I just returned from another race. I will sit down and go through all these replies. I did see a few questions. The one I can answer quickly is...

My motorhome is a 1988 Fleetwod Jamboree.

Also, does it matter that the generator does not work. The starter is out of it. Thanks Kevin.