Half Voltage at Living Room Lights

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.


New member
Dec 11, 2018
Raleigh, NC
First off this is my first post. I?ve used the forum several times before, but I'm finally stepping into the water and writing a post. Thanks for having me.

I'm pretty good with electricity, but I'm having an electrical problem that has me stumped and I?m hoping someone here can help me out. We have a brand new Jayco Melbourne 24 and the main lights in the living room are being problematic. The fixtures are LEDs and they occasionally work, but usually they are so dim you can't even tell they're on. When they work I am reading 13 volts at each fixture and when they don't work I am reading 7.6 volts. All the other lights in the house work just fine and read 13 volts - this includes over the dinette, over the sink, over the bed and in the bathroom. And those fixtures are all similar LED fixtures. The living room lights are on the same fuse as the porch light and the porch light works just fine.

I can't seem to find any rhyme or reason as to when the lights will work or not work. It does not appear to be related to other lights being on or off, being connected to shore power, generator power or battery power. It does not seem to matter if the RV moves or not, as if there were a loose wire, because we'll have it parked for days with the stabilizers down and sometime the lights work and sometimes they don't. I've checked for loose connections at the switches, but found nothing. I can't find anything else in the RV that correlates to this problem.

My best guess is one of the fixtures has an intermittent problem and is bringing the voltage down on all the fixtures, but there are eight of them and the wires are not easy to disconnect and reconnect due to the type of electrical connector used. I removed three fixtures and felt like i was going nowhere.

I know I can get this fixed under warranty, but we use the RV so much that I can't find time to drop it off at the shop, so I'm hoping to fix it myself. Any help you can provide would be appreciated.

Thanks in advance,
You may have a bad switch.  LEDs don't draw enough current to keep the wiping contacts on a switch clean.

Try working the power switch on and off several times the next time the lights dim.
If brand new, it would be going back to the dealer. Make an appointment for drop off and delivery back to you dates. Drop it off on time and show up at the correct time to pick it up. If not ready when it was supposed to be, just hang out at the dealership and be a pain in the butt to everyone there. They'll get it done quickly then. If they don't get the idea within the first hour, just start pointing out stuff wrong with the rv's people are looking at. When they lose a sale or two, the service department will miraculously find and fix the problem post haste.
Thank you everyone for the help. I have a few things to try here.

Isaac, you have a great point about a bad ground... unfortunately. Those can be tough to track down, at least for me. That will probably be  dealership thing.

Utclmjmpr, true about the polarity. I did check for that at the fixture and it is correct. Too bad, that would be an easy one.

Lou, do you mean to flip the light switch or the main power to the house? I've tried the light switch (a lot) and it didn't help. I did not think about the main power.

Unfortunately, my wife uses the RV for her business, so we need to find a time to get it to the shop when it won't impact the business. I think we'll just need to find the time and get it in there.

Thanks again,
RV shops are notoriously poor on diagnosis - too many of their techs are just parts swappers.  Finding an unusual or elusive problem (bad ground) is something only a few RV dealer shops could handle well. Or at all.  Plus they would probably keep the rig for weeks before doing something ineffective anyway.  I'd be inclined to find it myself if possible.

My first step (beyond what you have already done) would be narrow the problem down.  Bypass the switch and power source by running a temporary wire from battery + to the load side of the switch and see what happens. That would isolate problems with the power source & switch from problems in the fixture wiring and ground.  Another isolation test would be to run a temporary ground for one or several fixtures and see if that helps. If it does, you probably have a bad ground (high resistance ground).  Your trailer probably has a common ground wire serving those circuits, since it is rarely practical to give each one its own direct chassis ground.
I agree with Gary, and suspect a loose ground somewhere.  I would also check the 12v wiring for that circuit at the fuse panel for loose wires and tighten the connections. Trace the wires from the fuse panel and look for anything that might cause a ground.  Places where the wire goes thru holes and into walls.  If the problem is rubbed insulation on a wire in the wall have the dealer fix it since it is new.  I might have missed it in the posts,

Is it the entire string or just after a certain point in the string?
Is it possible that something is wired in series with the lights?
Thank you for all the great ideas. We ended up deciding to bring the RV into the shop. My wife was able to move her trips around and give the shop enough time to work on it. And with me working 60 hours a week lately I just don't have the time to put the proper effort into it. Besides, it's new, I feel Jayco should be the ones to step up and make it right.

I really don't care much for my local dealer, but we have a fabulous father-son repair shop nearby who does Jayco warranty work, so we took it there. He's been in business for 50 years (he's 73) and his son grew up in the shop. I'll post back here when they figure it out so as to help anyone in the future who runs across this post.

Thanks again,
It took a while, but the shop found the problem. There was Scotch Lock electrical connector that wasn't closed tight. They traced the wiring to a large bundle on top of the fridge and that's where the problem was. That's not where they expected the wires to go considering where the fridge is in relation to the switches and lights, but they found it. Thanks again for all the help.

Glad you got it worked out....You could have spent hours trying to chase that down.

Latest posts

Forum statistics

Latest member
Top Bottom