Best Digital Multimeter For RV Motorhome And Camper Trailer Electrical Repair

MY perfect kit for DIY RV electrical repairs.
MY perfect kit for DIY RV electrical repairs. | Source
A multimeter is a must-have item to troubleshoot RV A/C problems.
A multimeter is a must-have item to troubleshoot RV A/C problems. | Source

Why A Multimeter Is An Essential RV Tool

Unlike your home, your RV or camper trailer experiences quite a bit of jostling and bouncing over the course of the camping season. This movement can cause the electrical connections to become loose as they vibrate during transit. Common problems, such as you have in your home, are multiplied but are solved in much the same manner.

For the veteran camper, one of the most important and useful tools to have on board is a good electrical multimeter. While a simple test lamp may be utilized to solve simple electrical problems, a well made electrical multimeter can be used to test for breaks in the wiring or in malfunctioning circuit breakers. But just having a good electrical testing multimeter is not enough. You have to be able to use the multimeter correctly.

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Which Multimeter Should You Choose?

Just deciding which multimeter to purchase can be difficult because of the many brands and price ranges of electrical test meters offered online and in the stores.  But even a low priced multimeter will handle most electrical testing problems you will likely encounter in your RV.  The better models of electrical test meters  are naturally better made for durability and long life. 

No matter which multimeter you choose, be sure the test leads (wires with probes) are long enough and are of good insulation.  The better multimeters have good electrical test leads.  So don’t scrimp on the cost, you are going to be holding these leads in your hands!


Setting Up The Multimeter

Once you’ve made your choice, it is now time to learn how to use a multimeter.  It may seem confusing at first, but there are not that many different settings and probe positions used for most electrical testing procedures.  Install batteries as per the multimeter instructions which should come with the electrical test meter.

Because of the many different models of multimeter, it is necessary to determine the correct inputs for the electrical test probes.  Some models of multimeters require the electrical testing probes be in different inputs for continuity or voltage testing. 

Using The Multimeter For Continuity Testing

Of the two most common causes for RV electrical problems, breaks in wiring tend to be the hardest to solve. Using a multimeter makes finding the problem much easier. As per multimeter instructions, plug the electrical test probes into the proper holes and set the multimeter for OHMS. The particular wires or circuits to be tested must be turned off at the breaker box before being tested.

The multimeter uses a weak electrical current which will flow from one probe through the wire or circuit, and into the other probe if no breaks exist. The multimeter instructions will indicate the proper digital reading for an open loop OL or random numbers. When the circuit is closed the multimeter display should read 000.

Test the meter by touching the tips of the electrical testing probes together. The digital display should read 000. Some mutimeters give off an audible beep which allows the user to watch the probes instead of the display. This setting can be used for electric water heaters to ascertain continuity in the heating element. Any suspected break can be tested in this manner.

Top Quality Fluke Multimeters

Using The Multimeter For Voltage Testing

Many Rvs and camper trailers use both 12 volt and 120 volt systems.  The 12 volt applications are usually small light systems.  Set the multimeter to 20 volts for testing the connections.   With the electrical current on, the voltage on the display should read at least 12 volts when touching the connections with the probes.

All of the other electrical systems on board your camping unit will most likely be 120 volts.  Set the multimeter for 200 volts and make sure the electrical testing probes are in the proper inputs.  The digital display on the multimeter should read 000.  Insert the probes into an outlet, making sure the power is on at the breaker box.  The multimeter display should be in the 110-120 range.

Use this setting to test circuit breakers in the main breaker box and also GFCI type outlet applications in the bathroom and kitchen areas.  The electrical power to the A/C and H/W heater and various other vent fans should all test in the same range.

After you become accustomed to using your new multimeter, you will discover it can be used for your home, car, or RV.  A good electrical testing multimeter will pay for itself many times over and save you time and trouble in the process.              

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Comments 17 comments

Drwibble profile image

Drwibble 7 years ago from UK

I do a lot of electronic repair. I would be lost without my trusty multimeter. One thing I would advice is to buy some extra long leads with crocodile clip attachment. This come in very handy for fault finding across long wires which are fixed in place.

Randy Godwin profile image

Randy Godwin 7 years ago from Southern Georgia Author

Thanks, Drwibble! I planned to add the longer leads to the article and also include some in the ads. Too sleepy to remember, I guess. I use a multimeter lots too, both in my job and around the home.

Thanks again for reading and commenting!

kiwi gal profile image

kiwi gal 7 years ago

Interesting reading, not the best in the electrical department so this has been helpful, many thanks.

Randy Godwin profile image

Randy Godwin 7 years ago from Southern Georgia Author

It isn't as complicated as it looks, kiwi gal! This is a great electrical problem solving aid. Thanks for the comment and for reading my hub.


agvulpes profile image

agvulpes 6 years ago from Australia

Randy Godwin, these are good tips. As an old sparky and having blown up a number? of MM's in my day I would like to suggest to your readers that when measuring Volts to always start with the Higher settings and work your way down until you get a readout :-)

Randy Godwin profile image

Randy Godwin 6 years ago from Southern Georgia Author

Excellent advice, agvulpes! I tend to forget the simpler things. Thanks for the tip!

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xactdude 5 years ago

so I have just acquired a 92 5th wheel for free. of course there are issues, the most critical is the electrical. this trailer has had 2 lightning strikes. the first blew the control board on the frig and the 2nd has also disable the frig. after examining it i found the common wire has melted out of its insulation. no obvious burns on the board itself. how does one actually test the board for being bad? i never run a fridge on gas btw

Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

I would test the heating element instead, xactdude. If it is getting the proper voltage the board is probably okay. Those circuit boards will burn out fairly easily, in my experience.


xactdude 5 years ago

thx randy, that makes sense, i have a sneaking hunch the converter is gone also, the electric jacks are acting like they are low on voltage also and wont turn. can u advise where i can get the tech info on the voltage requirements?

Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

Are asking about the voltage requirements of the jacks or the converter, Xactdude? The converter should be putting out around 13 volts DC to the batteries when they require charging.

You might try checking the voltage at the jacks while operating them to find out if the batteries are storing enough amperage to work properly.


xactdude 5 years ago

will do it, thx

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grumpy55 4 years ago

we just purchased a 1979 Shasta TT to do some local camping. We knew there was going to be issuse, but because we have more time than money a fixer-upper was best for us. Trailer is solid, but when we plug it in to check lights and such it trips the GFI in our shop. Where do we start? Any help would be great..

john Patterson 23 months ago

I have a 31 foot fifth wheel camping trailer. All of my wall sockets are a hundred ten fold em all are working but the 12 volt light system is non functional. I have tested all of fuses with a multi meter and all fuses are good. I'm at a loss as to what to do next. thank you so much for your help

Randy Godwin profile image

Randy Godwin 23 months ago from Southern Georgia Author

Hi John! First, have you checked the voltage at the batteries while you have the lights on? If the converter is working properly you should be getting at least 13 volts when you use a multimeter on the battery terminals.

If not, then clean the battery ground(s) where it is attached to the metal frame of the trailer as a bad ground will also cause this problem. Check the battery fluid to be sure it is topped up as a low fluid level will not let the battery properly charge.

After checking all of these things, and you're still having problems with the 12 volt system, then it is probably a bad converter.. Feel free to ask for more info if needed. Thanks for the question, John. :)

Geoge 21 months ago

Thought my converter was bad so got new one still no power to 12v lights or a/c.all gfi work get 110. Have powe going to converter from 30amp breaker baffled.any thoughts ? All 15&20 amp fuses look good also the 2 40amp.

Randy Godwin profile image

Randy Godwin 21 months ago from Southern Georgia Author

HI George, have you cleaned the battery ground where it attaches to the steel frame of the camper yet? A bad ground will cause the problems you are experiencing and other weird things as well. Let me know if this solves the problem or not. :)


George 20 months ago

Thanks will definitely try this. Have had trailer for 3 yrs with no battery it was a fema trailer never had a problem. Till now. But will try ground anyway.

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