Friday, June 2, 2023


Would you attend this RV electricity seminar? Please tell us

RV Electricity

by Mike Sokol

Dear Readers,
I recently received the email below (at the bottom of this page) from a reader who goes into specific detail about how the RV technicians trying to repair his 12-volt DC problem went on an expensive ($1,550) and time-consuming wild goose chase. I’m a fix-it kind of guy, so I’m not going to bash these particular technicians for overcharging the reader. The problem goes much deeper than that. I blame much of this on a general lack of understanding of just how electricity actually works.

Now, I’m not going to tell you that diagnosing electrical problems is easy, because it certainly can get complicated at times. And I’m not going to tell you that a single RV Electricity seminar can turn technicians or RV owners into electrical experts, because I’ve been studying and working with electricity for 45+ years. But I will tell you that without a basic understanding of Voltage, Amperage, Resistance and Wattage, there’s little hope of correctly diagnosing any electrical problem quickly. No, without knowing how electricity actually works you’ll find that many RV shops just do part-swapping – plugging in random circuit boards and modules until something hopefully works. It’s what I like to call “Spray and Pray” diagnostics.

What to do about it? Well, for 2019 I have several RV shows and rallies interested in my RV Electricity seminars. But because of the crowding at these shows I only get 60 minutes of total time for my seminar, including a quick Q&A period at the end. Yikes, that’s really not enough time to teach anything substantial. Chuck Woodbury and I tried to put together an extended RV Electricity seminar at Quartzsite this January, but without sponsorship support or a spot to make my presentation in the main tent, there was no way we could afford to make that happen.

However, the huge Hershey RV Show 2019 is coming this September, and I’ve been given the 9 a.m. to 10 a.m. time slot each morning for my RV Basic Electricity seminar. This seminar will be free to the public, but once again it’s only 60 minutes total including any Q&A time, and there’s a LOT more I want to teach about RV electricity.

So here’s the plan. Since Hershey is a short drive for me (less than 90 minutes) and Chuck will be there anyway to meet with RV industry management, all we have to do is rent a hotel conference room in the area and I can present my 3-hour advanced seminar on RV Electricity theory and troubleshooting. However, the Hershey RV show doesn’t want me to present this off-site seminar during the week, so Saturday from 1 p.m. to 4 p.m. is the only possible time slot.

Chuck and I will have to pay for the separate room, workbooks and audio-video presentation gear, so we’ll have to charge for this advanced RV Electricity seminar. But you’ll receive workbooks from me as well as my 3-hour seminar with all the bells and whistles, plus up to an hour of Q&A time at the end. Cost will be $125 per person, which is what you normally pay for 1 hour of troubleshooting by an RV technician. I think that small investment will save you money the next time you take your RV in for service, since you’ll be better able to judge if the repair shop knows what they’re talking about for electrical repairs.

But to make this advanced training class happen we need to test the waters. So if you might want to attend this 3-hour seminar on Advanced RV Electricity on Saturday, Sept. 14, from 1 p.m. to 4 p.m. in the Hershey area (perhaps a 10-minute drive to a nearby hotel conference room), then please fill out the form below to pre-register. We’ll then contact you mid-June to confirm your attendance and formally sign you up.

As a prerequisite to this Advanced Electrical class, please take one of my free 60-minute Basic RV Electricity seminars at the Hershey show, even the one that Saturday morning at 9 a.m. That way we can jump right into more advanced topics without having to start from scratch.

And please take the survey below so others can see the level of interest. Right now I can book an off-site meeting room that will accommodate up to 50 of you in a classroom seating, but we don’t know if that’s too small, too large, or not worth trying at all.

So is a 3-hour seminar presented by me worth $125 to you? Please let Chuck and me know by taking the survey below and pre-registering, and we’ll move forward with getting it set up. I hate to charge for this, but due to the lack of support from the RV industry and lack of funds from the rallies, this may be the only way we can afford to teach Advanced RV Electricity seminars. And please comment below if you have any suggestions.

If you are interested in attending this or another Advanced RV Electricity seminar, please complete the following pre-registration form:

Email received recently from an reader:

Dear Mike,
I have been a fan of your newsletters and thought I would write to tell you of our experience this last week. My wife and I left our home in Wichita, KS, in our 33 ft. gas Class A coach headed for Tucson, AZ, and other warm spots for a couple of months. After driving for 7 hours, just before we reached Abilene, TX, all of our DC system went blank. Everything was lost, and in this coach that meant several important dashboard functions, including the heater, blower fan for heat, rear camera, blinker cameras, etc. The engine continued, and headlights and wipers were the only things still working.

We stopped at a local RV dealership and they had three techs spend all day looking for the short. I am not an electrical engineer so I was not much help. But we knew it had to be a major electrical line, because we soon discovered that our 250 amp/32 volt circuit breaker was fried. The tech thinking that was the issue, replaced the circuit breaker that we purchased at the local Napa parts store. With that in place, all systems came back on, and we thought we were fixed.

I pulled out of the RV lot and immediately all went blank again. So I turned around and all three techs started in again trying to find the short, all to no avail. We could have stayed over the weekend for another “expert” to arrive off Christmas break, or drive to a dealer that sells and services our brand.

Not wanting to sit, we left Saturday morning and drove 750 miles in 26 degrees across west Texas and New Mexico to arrive on Sunday night in Tucson, where a local dealership would get us in first thing Monday. That was the coldest drive ever below freezing going down the road with no heat, and a cold floor of the coach.

La Mesa RV in Tucson jumped on it Monday morning and in no time found the main electrical line that runs from the back of the coach at the generator forward and across the coach to where the house batteries are located on the passenger side under the steps. The manufacturer had run that main line, along with a hydraulic line that runs the rear jacks, through a small passage between the main I-beam of the coach and a cross beam. Normal driving over two years and 24,000 miles created an up and down, sawing motion that cut the electrical line in half exposing it to the metal frame; hence the short. Plus the hydraulic line was almost cut in half as well.

Two issues:
1. Why the manufacturer ran the lines through the small passage that exposes it to potential wearing with normal use? This is the main line that runs everything in the coach. Why put it at risk?
2. Why tie essential driving functions to the House system? Why cannot the heater and its blower be tied to the chassis battery?

The lesson is that if a short blows through that major fuse, then look for a short somewhere on the main positive power line. It takes a major short to blow that big of a circuit breaker. This one was hard to find, as the techs had to remove the two rear driver side wheels to get access to this small gap that was the issue.

The other lesson is perhaps the manufacturers should rethink their wiring protocol. Keeping essential systems tied to the chassis is not a substantial risk of running that battery down. We are fixed now, after 5 cold days, and out $1550. Wish I was an electrical expert and knew what to look for. —Marc Colby, Wichita, KS

Thanks for your email. I’ll cover this in depth in my next RV Electricity Newsletter due out the end of January. See you all then.

Let’s play safe out there….


Mike Sokol is an electrical and professional sound expert with 40+ years in the industry. His excellent book RV Electrical Safety is available at For more info on Mike’s qualifications as an electrical expert, click here.



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4 years ago

Mike, Do your seminar in conjunction with the RVillage rallies. Either before or after the dates if fine with me. See you in March event.

Matthew Blome
4 years ago

I would be very interested in an advanced seminar for RV restoration. There seem to be legions of people restoring old trailers searching for plans etc, without a lot of help unless they have some electrical training. Like a lot of folks, I am an amateur restorer and enthusiast, but an absolute neophyte when it comes to electricals. I have seen literally hundreds of unanswered requests for electrical diagrams and design help on various RV-related internet forums.

I have bought every 12V and RV electrical book I can find but those have limited utility (they assume a base of knowledge, are dated, or irrelevant [voltage drop over distance is important, but I can mitigate it completely as an issue by spending $3 more on a heavier wire]) . I, for one, need information on the design of the integration of 12V and 110V systems, basic wiring connections for RVs, integration of convertor, battery, and distribution panels, shutoff switches, and related items.

Other crafts such as sheet metal, welding, fiberglass, painting and even plumbing are more approachable for self teaching, but electrical is different. Local electricians are loathe to touch anything 12V, and local RV places don’t want to touch vintage restorations or systems. I have called dozens in my area.

I think this is an unanswered niche and would love to write a book or guide myself, but need to get the base knowledge going. Hopefully you guys can get out across the nation to other areas. The Hershey PA show would be fun to go to but is not practical.

Thanks for any help,


Chuck Woodbury
4 years ago
Reply to  Matthew Blome

Matt, we will keep you posted on other locations.

Mike Sokol
4 years ago
Reply to  Matthew Blome

Matt, I actually have a very strong background in 12-volt DC systems, but just haven’t written about them much. However, that sounds like a great topic for an extended seminar at some trade show or rally. How about this? I’ve been invited to do a few 1-hour seminars in Goshen/Elkhart, IN this year. While my introductory (free) seminars there will have to cover the basics, it might be possible to find space to do a few 3-hour (advanced) seminars on specific topics such as DC-power design and troubleshooting in RVs. Again, I’ll have to charge $125 per seat for those advanced classes, but they’ll include a workbook, my 3-hour seminar, plus 1-hour Q&A. If anyone might be interested in attending one of my advanced 3-hour seminars in Goshen/Elkhart, and willing to pay $125 per seat (or $225 for 2 seats), then please let me know. I can create a 3-hour advanced class on just about any electrical topic, so if you have suggestions for seminars in addition to RV 120-volt AC systems and RV 12-volt DC systems, let me know as well.

Matthew Blome
4 years ago
Reply to  Mike Sokol

Gentlemen, thank you for your responses. I live in the Kansas City area and Elkhart would definitely be easier than Hershey, PA. I think that cost would be definitely manageable. I am scheduled to attend a three day Vintage Trailer restoration event in March of this year for significantly more. We also have at least 3-4 RV shows in this area here between now and the end of March if it would be advantageous for you to come out here, though I believe the agendas for the first two are pretty well set at this point.

I would be happy to discuss some additional specifics in direct correspondence if it would be easier. My email address for RV oriented topics is

I am in the process of reading through some of the articles on the No Shock Zone website and am working the wiring for a 1955 trailer this week.

John Whitney
4 years ago

I just fixed a short in one of the 12 v lighting circuits. Not only am I an electrical Engineer but also spent 10 years as a Plant Engineer, learning a ton of things from my licensed electrician. 1. Identified all lights on the circuit. 2. Checked The lights and fixtures for obvious problems. 3. Identified one door switch that looked suspicious and took it apart. Totally rusted out and contacts touching steel. 3. Removed from circuit, and checked both wires to ground. Both were still shorted to ground. Since CB was still open, one should have read very high ohms. 4. Checked other baggage door switches. Another was also rusted out. Removed from circuit. 5. Energized CB and rest of lights now functioning.

My purpose in this essay is to demonstrate that a little 12 volt electrical knowledge and an understanding of electrical troubleshooting can turn most people into basic trouble shooters, saving themselves a lot of money.
I DO NOT recommend that anyone without detailed electrical training tackle 120 volt troubleshooting and repair.

Mike Sokol
4 years ago
Reply to  John Whitney

John, yes you are correct. Once you understand the basics of electricity including how voltage, resistance and current interact, then a lot of troubleshooting can be very straightforward. For me it’s all about predicting what voltage, resistance or amperage I expect on a particular circuit. Then if a measurement deviates from the expected value, you just need to envision what circumstance could possibly cause what the meter or trouble light tells you. However, most RV owners don’t even know how to use a meter to test a fuse or bulb, and that’s entry level troubleshooting. My plan for this seminar is a bunch of hands-on demonstrations starting with simple things like testing fuses and bulbs, then working up to measuring simple circuits like a battery, switch and LED bulb. I’ll save the 120-volt AC testing for my advanced RV technician classes.

Reg Gray
4 years ago
Reply to  Mike Sokol

Very often you have to be careful on 12 V stuff as I was ones working on the rear window on my station wagon and it had 3 control locations each with a up and a down control . One at the front, one at the rear by the back tailgate door, and the last in the key at the back door. This took a lot of searching but would never be properly fixed until I got the wiring print from Ford. Each control location was fed from a different fuse so when you took the fuse out that was marked on the fuse panel it still worked from two other spots, then I ended up shorting out the feeds from the other locations to trip the fuse so I could find all 3 power sources that controlled the rear window. So always try to get a wiring diagram first and save a lot of time.

Mike Sokol
4 years ago
Reply to  Reg Gray

The ability to read a schematic is super important to troubleshooting anything electrical. However, since most RVs don’t have a pre-built wiring harness the actual build can vary from the schematic. Plus you need to double-check the wiring colors since it appears that the builders will sometimes use whatever color wire they have in stock. Getting a schematic can be challenging especially years later, so if I were buying a new RV I would insist on getting a build schematic in-hand before signing a contract. Then make a few copies of it for future repar reference and keep the master schematic in your house. Without a schematic for reference you can easily double or triple your troubleshooting time. And time is money, as they say.

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