Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the RV Handbook and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses why an RV’s lights go out while appliances still work.
Over a week ago all the interior lights including the porch light, exhaust light and exhaust fan went off. Just when my husband seems to have found the problem the fuse blows out again. All the electrical outlets work and so does bringing in the steps, microwave and refrigerator. What can be causing this? He has looked and done everything possible. —Rosie
There are two different electrical systems used in your RV: 120-volt AC and 12-volt DC. The 120-volt AC system is similar to your home and supplies power to the outlets, roof air conditioners, and any appliance that runs on 120-volt power. Typically, these appliances such as the microwave and refrigerator are plugged into a dedicated outlet rather than hard-wired directly. 120-volt power is supplied from an outside source such as the campground pedestal or a generator to the distribution center, which has circuit breakers for each application.
The 12-volt DC system utilizes deep cycle batteries to provide power to the interior lights, vent fan, and any appliance operating on the LP mode. The house batteries supply power through the distribution center with automotive-style fuses, which I assume you are referring to that have “blown.” So, you have an issue with something on the 12-volt DC side of the system, since the refrigerator and microwave are working.
How to troubleshoot why the lights go out
My guess is you have a light fixture that has a loose connection causing a short or a wire that has been compromised with either a cut or screw driven through. These can be hard to find as they can be intermittent. I would start by removing all bulbs in the light fixtures and reinstalling one by one to see if you can get the fuse to blow. That will identify the faulty light or even wire.
You may need to run a new dedicated wire from the battery to individual lights. This is a long process but is easier than trying to trace wires that are embedded into the sidewall or ceiling!
Typically, the exhaust fan is not on the same circuit as the lights and should have a dedicated fuse just for that. If it does and both the fan and light fuses are blowing, then you have a wire touching somewhere. Take a look at the fuse panel and identify each circuit and isolate what is actually blowing or not working.
Read more from Dave here.
Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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