Short circuit troubleshooting

[jabrabu]

I have a 2018 Chateau 31E, and the 15A fuse labeled "Driver's Side" keeps blowing. This circuit powers the lights in the bedroom, bunk area, and over the kitchen sink. When I replace the fuse it immediately blows again, so there is a short somewhere in the circuit. I looked at the wiring behind the fuse panel, and I don't see any obvious damaged/shorted wires. These lights are all LED lights.


If I turn all the light switches to off and the fuse still blows, I assume this means the problem is not in the lights themselves, right? If this happens, what are my next steps to isolate the fault?

[cpmath]

Well, if it's a 2018 model is there a reason you're not taking it back to the dealer, it is under warranty still.

[randyj]

We had the same problem with our 2017 Quantum KM24.
Took it to an independent RV repair facility for diagnosis and repair.
In installing the cabinets above the dinette during build out, apparently a staple was stapled through the wiring that supplied power to the lights or rocker switch that when activated caused the 15 amp fuse to blow.
Four hours to diagnose and repair.
I paid repair facility directly and Thor reimbursed me 50%.
I suppose if I had taken it to the selling dealer it would have been 100% covered but then I was at their mercy to schedule and repair on a timely basis, which I did not want to do.
Hope that helps.

[jabrabu]

Originally Posted by cpmath

Well, if it's a 2018 model is there a reason you're not taking it back to the dealer, it is under warranty still.

It is now over a year old, so it's just out of warranty. It's also a hassle to schedule dealer work, and over an hour drive each way to the dealer. Also, the last time it was at the dealer, I had them check/repair 4 items, and 2 were partially done and 2 were not done at all. So I prefer to do most work myself to ensure it's done right.

[16ACE27]

Troubleshooting a short as you describe is very difficult and requires both a true schematic diagram as well as a true wiring diagram.

Basically, you need to determine where the half-way point of the circuit is and disconnect the + lead supplying the second half of the circuit.
Stick your fuse in - if it still blows, the short is upstream, if it doesn't, the short is down stream.
Now split the offending half circuit again and test again. Continue half-splitting until you find the problem.

[abjbrtd]

Originally Posted by Tfryman

Troubleshooting a short as you describe is very difficult and requires both a true schematic diagram as well as a true wiring diagram.

Basically, you need to determine where the half-way point of the circuit is and disconnect the + lead supplying the second half of the circuit.
Stick your fuse in - if it still blows, the short is upstream, if it doesn't, the short is down stream.
Now split the offending half circuit again and test again. Continue half-splitting until you find the problem.

A wiring diagram may not show as installed. When you find the wire with the trouble is when the real fun begins.
If you have a volt/ohm meter, they cost about $10 at WalMart, try it this way.

Disconnect both wires at the fuse, 1 on the fuse and the other on the ground bus. Test for the short.
If it's gone you get to GO ahha…

Then follow Tfryman's instructions, start about 1/2 way from the fuse.
The meter will pay for itself pretty quick.

Good luck and keep us updated

[Cason61]

Originally Posted by randyj

We had the same problem with our 2017 Quantum KM24.
Took it to an independent RV repair facility for diagnosis and repair.
In installing the cabinets above the dinette during build out, apparently a staple was stapled through the wiring that supplied power to the lights or rocker switch that when activated caused the 15 amp fuse to blow.
Four hours to diagnose and repair.
I paid repair facility directly and Thor reimbursed me 50%.
I suppose if I had taken it to the selling dealer it would have been 100% covered but then I was at their mercy to schedule and repair on a timely basis, which I did not want to do.
Hope that helps.

And depending on how long they would make you wait in line versus the independent guy, I'd say the new guy was faster getting to it.