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

itsabouttime
Explorer
May 18, 2013
Although either a digital or analog meter can be used for most work, each has it's advantages and disadvantages. An analog meter gives a quicker look at voltage, polarity and even resistance. A digital meter gives the illusion of greater accuracy. I say illusion because a cheap digital meter can be just as inaccurate as a cheap analog meter. A dirty voltage source is more easily tested with an analog meter. With either type of meter, it's good to use a precision voltage source such as a new battery for an occasional calibration check. I carry both kinds of meter.
Mandalay_Parr
Explorer
May 18, 2013
They are also called DVM's. Digital Volt Meters.
deleted-2
Explorer
May 18, 2013
I have a Fluke 189
Something it has is a temperature probe feature.
I use that a lot actually.
path1
Explorer
May 18, 2013
And can't beat the price when you get one free like I did last month from Harbor freight. Also last week and they had a coupon for another free one for Memorial day, if you pick up the coupon before. (Their way of getting you in store one more time I guess)The one free last month, I thought for free it wouldn't be very good. Measured 110 with good one and free one, same reading. I have 2 coupons in front of me right now if anybody with high-tech knowledge can show me how to send it over internet.
LostinAZ
Explorer
May 18, 2013
I carry a $4.95, $2.00 on sale from Harbor Freight DMM in the 5th wheel at all times. Is it really accurate in measuring ohms? No! But for casual voltage checking, shorts, broken connections, intermittent connections it is perfectly adequate. For real serious electrical diagnosis I use a $200 plus Fluke DMM that has multiple features for measuring multiple electrical items very accurately when needed. But for most RV needs a 10% error possibility IS GOOD ENOUGH. I still prefer the old style analog meters that were made by Simpson and Triplett but they are becoming obsolete and expensive if they can be found.
Vulcaneer
Explorer
May 18, 2013
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.
naturist
Nomad
May 18, 2013
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.
WyoTraveler
Explorer
May 18, 2013
The only thing missed was ohms law.

E
______
I · R

The 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.
ScottG
Nomad
May 18, 2013
VOM (Volt Ohm Meter) was common vernacular for the old style analog meters but still fits for digital meters too.
2oldman
Explorer II
May 18, 2013
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.

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Digital Multimeters- An RVer's Best Friend

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