I read many, many posts regarding electrical faults in all types of RV's. The one best way to troubleshoot faults like this is using a digital multimeter (DMM). Many folks on this forum own and use digital multimeters, with great success. I know these things can seem a bit overwhelming to people who have little electrical knowledge, but it takes only a bit of interest and studying to learn how to use a DMM to fix your electrical problems. Even the cheapest DMMs are suitable for basic troubleshooting, so adding one to your tool kit is affordable and highly advisable. Then check out online sites that teach about using DMMs, such as:Multimeter Use They can be used to check battery charging status, checking fuses, finding battery drain, troubleshooting signal / tail lights, shore power test, etc.Perhaps some others could join in by telling us what kind of meter you use, and some more ideas about uses for it.

Heck I've know people to be afraid to stick the probes in anywhere there's electricity.. let alone understand what the meter says. And I've more often heard them called a VOM, not a DMM.

VOM (Volt Ohm Meter) was common vernacular for the old style analog meters but still fits for digital meters too.

The only thing missed was ohms law. E ______ I · RThe other thing is sometimes checking turn signals you need a plain old test probe with a 12 volt bulb.Tracing down bad grounds you need to move the black ground lead on the meter to find them.

I've got a relatively cheap one, as I recall it was about $40 from Radio Shack. It measures voltage up to 600 volts or so, amperages up to about 10, resistances up to a few meg or so. And even AC frequencies, as well as capacitances and a few things I don't know what they are for. It is great for checking CG power pedastals for voltage open or under load, circuit/device continuity, generator performance and frequency accuracy, electronic parts, etc. Very handy device.

Checking intrinsic battery drain. A DMM can be specific. Where a test light only tells you if current exists or not. Also handy to measure brakes voltages, amps at the magnets. Much moreprecise than Analog units.

Digital Multimeters- An RVer's Best Friend | Good Sam Community

20 Replies

pkunk
Explorer
May 19, 2013
I have that meter. It is every bit as good as my Fluke plus it has 2 ranges of DC amps. This is what every RV owner needs who wants to know what their 12V system is doing.
Tom_M wrote:
The most useful meter I've found is a clamp-on style ammeter. With a clamp-on meter you don't have to break a circuit to measure current. Most clamp-on meters will only measure AC current so you will have to spend a bit more for one capable of measuring DC. I spent $80 for the one I have. Sears sells a meter for about $60 that looks appealing.

Craftsman clamp-on
mr__ed
Explorer
May 19, 2013
I started my electrical career as a teenager and built several kits, including a VTVM (vacuum tube voltmeter) by Heathkit. So my first "multimeter" used vacuum tubes and had to be plugged in to a 120 VAC outlet. Today, the least expensive DVM from Radio Shack is much more accurate than that old VTVM was and runs on a battery. How much we've progressed.....:C
YC_1
Nomad
May 18, 2013
I'm an ET with 40 yrs of experience and concur. However, just one little caveout. A digital meter can indeed trick you so a handy 12 volt bulb tester as suggested can be very useful and user friendly. Checking fuses will give you a simple go/no go visual. Checking trailer connections won't get you tricked by showing you voltage but when you plug things in it does not work for example.

Not having to look at a meter versus seeing a light is sometimes less painful too. Twisting and turning while making several fuse test under a dash can be difficult.

So I highly recommend you have one of each in your tool box. The test light is about $10.
Gadget_Guy1
Explorer
May 18, 2013
Tom_M wrote:
The most useful meter I've found is a clamp-on style ammeter. With a clamp-on meter you don't have to break a circuit to measure current. Most clamp-on meters will only measure AC current so you will have to spend a bit more for one capable of measuring DC. I spent $80 for the one I have. Sears sells a meter for about $60 that looks appealing.

Craftsman clamp-on

I use one of these also but I also have the cheap ones from Harbour freight that I have in every vehicle, every tool Box , every work bench and these are the ones I use all the time. At 5 bucks they are cheap enough but also very accurate that if someone needs one I just give them one.
noteven
Explorer III
May 18, 2013
delete.
Tom_M1
Explorer
May 18, 2013
The most useful meter I've found is a clamp-on style ammeter. With a clamp-on meter you don't have to break a circuit to measure current. Most clamp-on meters will only measure AC current so you will have to spend a bit more for one capable of measuring DC. I spent $80 for the one I have. Sears sells a meter for about $60 that looks appealing.

Craftsman clamp-on
Dakzuki
Explorer II
May 18, 2013
This is a nice inexpensive one. Big digits and a wrist strap so you can use it one handed. It also takes standard banana plugs so you can set up with some Pomona leads and alligator clips or whatever. I have three...one at home, one I fly with (work), and one in the RV.
BB_TX
Nomad
May 18, 2013
Anyone not comfortable using a DMM/DVM/VOM/etc would do well to build ( or have someone help build) a test fixture as described under "outlet testing" on this web site. No probes to worry about. Just plug it in before plugging the RV in.
prolandsurveyor
Explorer
May 18, 2013
Fluke makes the get ones...I work on havc and I use mine several times a day.
WyoTraveler
Explorer
May 18, 2013
Although I have some pricey voms most of the cheapos will do the job. I have. $500 digital but the Harbor freight $6 model is fine. Or $17 Walmart vom. My pricey unit shuts off by itself etc. & more accurate but this ain't rocket science. Stick with the ceaper ones. Once you learn what they can do then pop for a better vom. I can remember when a 20,000 ohm per volt meter was top of the line. Pretty expensive too. Buy a cheap one and use it. You can learn alot.

Forum Discussion

Digital Multimeters- An RVer's Best Friend

20 Replies

About RV Tips & Tricks

Related Content

Multimeter recommendation?

Multimeter Question

Best multimeter

Multimeter Calibration?

Multimeters