Bad 12 light wiring...somewhere

[jtstromsburg]

Our Polamino Sabre 34TBOK is just out of two year warranty and I've got an issue I wish was covered. Maybe still can be as it was on my list for dealer warranty after our first season. Unfortunately at the time, they couldn't replicate the issue. Previous symptoms were the 20a fuse for bunkhouse, pantry, and ok lights tripped randomly, but often. The dealer had no problems either time they had it, but it's continued. We are on a trip in the black hills, lights quit working, fuse hasn't tripped, but the fuse and wiring at bunkhouse and pantry switches was super hot. At this point I just removed the fuse. I found a lose wire at one switch, a set of three crimped together, and recut those wires and added a new wirenut. Didn't fix so that's when I removed fuse.
So question is what would the situation be to not have a blown fuse, still no lights, and wiring gets hot if I leave fuse in?
Hmmm

[Fly YX]

I have seen in aircraft that the wire will rub on something and short but not enough to blow the fuse or its a bad connection/corrosion. if its on a 20 a fuse it should be on a 12 gauge wire. If it is not the wire will get hot before the fuse will blow. If its just lights especially LED you do not need them on a 20amp circuit. Look at any place that the wire is going through a hole and see if it has rubbed through the insulation like the metal frame or the slide out where it will flex.

[jtstromsburg]

Thanks Fly YX. I'll check out any places I can get to.

[Flybob]

Possibility someone drove a screw into the wire and you have a high resistance short. It could be had to find, but one possible thing to try is locate an infrared camera and scan the walls inside and out while the fuse is hot. Depending on where you live, your fire dept may have one, They may scan it for you for a nice donation to the steak fund.

[jtstromsburg]

Good idea on scanning walls. Temp gun could maybe work but would take longer I suppose. I know if I throw a 30a in the fuse spot, it handles the heat, at least for a few minutes.

[Fly YX]

The thermal camera is a good idea but not for troubleshooting wiring in that way you can permanently destroy the wiring and or cause a fire leaving it hooked up that long to get hot. Use a Multimeter and break the circuit up and check your amperage. What I mean is hook the meter up to the beginning of the circuit next to the fuse then work your way back from the end of the circuit physically disconnecting Junction points like where you have a splice in The Wire. Make sure everything is off by the way. Then when you have no amperage in that section whatever part of the circuit you are in the problem is Upstream of what you disconnected. Don't know if I'm making any sense or not Jack Daniels does that to me. Lol

[jtstromsburg]

Well as long as jd hangs with me while I trouble shoot we should be fine. [emoji12] probably won't work on it till we get home but if we have a day just hanging around camp, maybe will give a look again. Lots to see and enjoy in the black hills so not too worried about the lights right now. But still thinking about it

[MacGumbo]

First, make sure all 12v lights and devices are off then pull the fuse.

Take a multi-meter, set to ohms and check across the fuse terminal and ground. It should read open. Be sure to check both fuse connectors unless you know which side is opposite the 12v supply.

If you get any continuity, you have a short somewhere in the line.

[Fly YX]

If you do this make sure utest what side the 12 volts are on the fuse do this by putting the meter on dc v and between ground and one side of the fuse holder and then do the other side of the fuse holder. ( With 12v fuse removed ). Whatever side the 12 volts is on do NOT have the meter on resistance when voltage is applied to the circuit. Depending on the meter. This can cause damage to the multimeter. Then you can work your way back to the fuse like the way with checking amperage. If you can't find it with the switches​ off then you will have to take out the light bulbs. ( If any load is on the circuit when you do this you will read through the load). BTW is any of the lights LED or incandescent? And if LED is it a retrofit or factory fixture? The only why I asked is some of the cheap eBay special retrofit led bulbs have cheap voltage regulators and I have see them get hot enough two melt the solder on the PCB board and the LEDs come out. Do not think this is the problem but you never know.

[youroo]

Like FlyX said sounds like a "Wire Rub Through", after Driving and setting up camp again does it appear? Since the Dealer could not "Replicate" sounds like a "Wire movement/Rub Through Short"! Hard to locate,but use the Meter as suggested! Youroo!!

[jtstromsburg]

Originally Posted by Fly YX

If you do this make sure utest what side the 12 volts are on the fuse do this by putting the meter on dc v and between ground and one side of the fuse holder and then do the other side of the fuse holder. ( With 12v fuse removed ). Whatever side the 12 volts is on do NOT have the meter on resistance when voltage is applied to the circuit. Depending on the meter. This can cause damage to the multimeter. Then you can work your way back to the fuse like the way with checking amperage. If you can't find it with the switches​ off then you will have to take out the light bulbs. ( If any load is on the circuit when you do this you will read through the load). BTW is any of the lights LED or incandescent? And if LED is it a retrofit or factory fixture? The only why I asked is some of the cheap eBay special retrofit led bulbs have cheap voltage regulators and I have see them get hot enough two melt the solder on the PCB board and the LEDs come out. Do not think this is the problem but you never know.

2015 fiver. All lights are factory LED's.

Thanks everyone

[DrLewie]

Could it be a bad ground? The heat part is concerning, but intermittent no power happened to me and the problem turned out to be a lose ground wire in a wire nut FR had something like 6 lines running into a single wire nut.