The fuse to the interior lamps and the fuse to monitor panel/radio both blow when the battery is connected, via the disconnect switch even if the all the light switches are off and no buttons on the panel are pushed.What should be my next step to troubleshoot this?The van is under warranty and I have an appointment, but I'd like to learn something in the two weeks before they see me or maybe even fix it.TIA,Eric

You have a short to ground somewhere along the way. If it's under warranty you might not want to mess with it. Only way to find it is first isolate the wire that is shorting. With the battery disconnected remove the wires from the offending fuse at the panel. Using an Ohm meter you can check to see where there is a path to ground on one of those hot wires.Put one lead of the meter to a known ground and the other to the wires, one by one. When the Ohm meter registers a drop in resistance there is a circuit between that wire and ground (i.e.: a short). After you find the wire (or wires) with the short then you have to physically trace that wire(s) to find the short, probably frayed where it goes through a metal support somewhere.

Total agreement with Dennis MM.You don't want to make a boo-boo and leave evidence of tampering. Most of these places are strict about warranty conditions violations. A lot of troubleshooting leaves tattle-tale marks. Ask the service manager. "I want to learn".A component failureA wiring failureDownload a FREE PDF bookTHE 12-VOLT DOCTOR'S HANDBOOK. It does a great job explaining the basics and the material needed to do a job just like yours. It's about sailboats but electricity doesn't know the difference.

bulbs have to be removed or you will measure resistance of bulbs or what ever else is in the circuit. If a wire runs to several bulbs you would to remove bulbs then disconnect wires to isolate which area is shorting out. Could be as simple as a bad socket or as bad as a crushed wire inside a wall. I would let them work on it.

You guys seem to be unanimous in your opinion that I let the dealer fix this and I think you've convinced me. I've done all the visual checks of the wire that I can see but when they disappear into the looms, I'm lost. Thanks,Eric

Have you done recent modifications or upgrades and possibly shot a screw into a wire? Backtrack

Troubleshooting a short | Good Sam Community

22 Replies

eric1514
Explorer
Oct 31, 2015
I did pull the power panel and the monitor panel to see what I could see, which wasn't much. In the case of the monitor panel there was a bundle of wires to wiggle but that's it. As far as the control panel, there is a large door above the thing that let's you look down on it and touch and pull wires and connectors all you want. You don't gain anything removing it forward. I unscrewed one of the lights from the ceiling and was going for another when my wife told me to cut it out.

The coach is under warranty and you've warned me to not tamper too much or they might blame me. But, as I type this, I remember the radio is on the same circuit as the panel so I might sneak out there tomorrow and pull it.

I do kinda like the life support idea, too.

Eric
time2roll
Nomad
Oct 31, 2015
Just a couple screws and the entire power panel slides out.... what are you waiting for?
You have to get in there and look.
Spridle
Explorer
Oct 31, 2015
From what I can see in the picture, it looks like you are testing the 7th circuit. The seventh wire is white and cant see a colored stripe and is going down through the metal fuse enclosure. There is no plastic bushing to protect the wire from shorting out on the sharp edge. If that's not the problem, install a bushing. It should have been there to begin with.
MEXICOWANDERER
Explorer
Oct 31, 2015
Tell them your wives Life Support machine similarly quit. Otta speed things up...
eric1514
Explorer
Oct 31, 2015
Well, there's no joy in Mudville. Mighty Eric has struck out. I wiggled every wire I could find both inside and out and no luck. Thanks all for your help, but this is a job for the dealer and hopefully a warranty issue.

Eric
Chris_Bryant
Explorer II
Oct 30, 2015
That will work. I use short jumper wires so I can lay the light out where I can see it- some pics I took for my blog:

Note that the light will light dimly if there is anything turned on, it will light brightly with a short.
Coolerman
Explorer
Oct 30, 2015
Yes, you have it! Start wiggling and watch the light or have someone else watch it.
eric1514
Explorer
Oct 30, 2015
OK, so bear with me. I bought a test light at HF.

Now, I connect one end of it to one of the fuse holder terminals and the other end to its counterpart. The bulb lights. So now, without leaving any traces of me tampering, I should be able to wiggle wires and see if the light flickers, correct?

Too bad it's cold enough to snow outside right now.

Eric
Matt_Colie
Explorer II
Oct 30, 2015
The test lamp is the only way to go, but you also have the problem of making the dealer respond to a warranty issue that should not be ignored.

It is very easy for the assembler to trap a wire that will get crushed and short to the frame later. These can be very difficult to locate. But, if you are going to try, get the test light lit where it should be a fuse and start taking things apart. The easiest ever was a shorted bulb. So, turn each light switch. if you are not sure which is on or off, remove and disconnect the fixture. Do not reconnect it until you are done. If you get them all apart (remember those lights in hidden places - too) and the test light is still on, then you have a wire damage issue.

Before the depression, I did a lot of this sort of work both for boats and RVs. Things like this can be a real bear to locate. I have found that it worked best to try to start with the light that is closest to power first. They are typically "daisy chained". So, if you break the circuit there and loose the short, you can put it back together and keep going.

Good Luck

Matt
Coolerman
Explorer
Oct 30, 2015
One good way to test circuits without investing in a fuse companies stock... ;)

Use a +12V light bulb like a 1141. Get a red and black 16ga wire 12" long and attach alligator clips on one end of each wire. Solder the other end of the red wire to the center contact on the base of the 1141. Solder the black wire to the side of the base. Remove the fuse in question and clip it to each side of the fuse holder. If the light lights, there is current flowing indicating a short. The brighter the light the more current there is flowing. A bright light could indicate a direct short to ground a dimmer light could indicate a short to another circuit.

Since the 1141 bulb will only draw about 1.44 amps, it won't allow enough current to flow in the shorted wire to get anything hot enough to melt. This allows you to safely troubleshoot the circuit live.

Wiggling wires will sometimes make the short go away which you can instantly see as the bulb will go dark!