Converter/ Furnace Issue

[CPCole]

I have a 2013 Starcraft Autumn Ridge 336 RESA TT. My issue is that if I have my furnace and my converter running at the same time when connected to shore power or my generator the furnace or the converter makes a grinding sound like there is something caught in the blades. While the furnace is running just on battery it is fine. If it is running and I flip the breaker to turn the converter on the noise comes back. I then shut off the heat and the noise goes away.

So the bottom line is that when both are running it is very loud grinding type noise and if one or the other is turned off it is quiet. Anyone ever come across this weird issue? Thanks in advance.

[Grumpy]

Could be the cooling fan in the converter due to the extra electrical load from the furnace motor and it's going bad.

[Shokyle1]

X2 that is what I would look at first

[CPCole]

So it is only pulling an extra load because the furnace is 12V? It doesn't do it if I turn on microwave or AC. So if I can isolate it to fan I will probably have to replace converter I assume. I'll try to isolate it more tomorrow. Thank you.

[Route 66 Traveler]

The AC and microwave use 120vac, the converter supplies 12 volts DC to the furnace and everything else that uses 12 volts. The cooling fan in the converter comes on when the 12 volt load starts to generate heat. Could be the fan blades are very dirty, or it is hitting something that found its way into the converter.