Interior fuse keeps blowing

Other things that may be running are the radio memory and the propane detector, carbon monoxide sensor. Or there could just be a wire someplace that has been compromised by a staple or other sharp edge.
This one is going to take some detective work by removing one thing and then another to see what happens. You really need an ohm meter to try to track down this shot.
I would not replace the fuse and leave the rig though.

As suggested, do some checking as maybe something else is running on the same circuit. Simple check, turn the fridge off, pull the suspect fuse, get a meter and measure the resistance on the outgoing side of the fuse. It should read "open". If not, then something else is connected to the circuit such that as the fridge controller "works", it heats up and eventually blows the limit of the fuse.... maybe. Of course, it will help if you identify the size of fuse involved and the fridge model to look at things like "draw".

One thing for sure is that it is not a short circuit. If it was the C/B would blow immediately. So it's got to be an overload.

Turn all lights off and check the current flow. Should be zero.
Then turn on one light at a time and discover where the current goes to.

Otherwise you need to discover what is on that circuit and where the power is going.

Main power cord is 120vac and does not really have an effect on the 12vdc system.

Call the tech back and have him look at the problem.

I'm curious, if you are not using the RV, how do you know the fuse is melting?

What is on the circuit? It should be easy enough to check what does not work after the fuse is melted or removed.

It would also be very handy when trying to offer advice if we knew what RV you have.
:h

It would be good if you could find a schematic for your wiring...might help to eliminate some things. Could you have a moisture problem getting into a light, etc. ? When you get if fixed please post what you found to be the problem.

RvNewbieFl wrote:
Hello, I keep blowing the number 9 fuse labeled interior lights. I'm not using the rv. Only have the freg (on electric mode) running. Originally the fuse would only last a few hours, however after the tech replaced the main power cord, it lasted about 18hours and blew again. Any suggestions helpful thanks.

So, when it blows does the refer stop working?

Dick_B wrote:
One thing for sure is that it is not a short circuit. If it was the C/B would blow immediately. So it's got to be an overload.

Not really, in the industry we would call this a soft-short. Either way, there's no rule that says it isn't a short unless it blows a fuse or a breaker immediately.
Also, the short may not exist until something else happens (movement, something turned on, etc) thereby not tripping the circuit protection until a later time.

I have the same problem with my bathroom fan. Put in a new fuse and it lasts 2-3 times and blows again. Everything else works fine.