Coach Lighting Short

[papa45]

Spring Break, last week, the 12V bedroom ceiling lights went out. Fuse is good. Other lights on the same circuit work OK. There is no power to the wall switch. Can't find anything loose on the power panel or converter. I assume something shook loose, but electrical code should not allow any connections that are not located inside an electrical box. I can't guess how the wiring is routed inside the floor and/or walls. Any suggestions?

[MrWizard]

Usually the ground follows the hot.. The two are run parallel
The loose connection is either behind that fixture or at the previous fixture in the circuit chain

[papa45]

I got a schematic from Fleetwood and was able to confirm that all my 12V circuits are color-coded. Lucky me!

I checked out a couple of things to make sure I hadn't overlooked anything and discovered that I do have power to the switch. What I don't have is a ground.

New question: How and where are the 12V circuits grounded? To a common bus somewhere? To various points on the vehicle chassis? Of course, the ceiling light ground wires just disappear into the ceiling and I have no idea where they go.

[bdpreece]

papa45 wrote:
bpreece: Will that cable tracker work through a floor or a wall, particularly when I'm not even sure where the wire is located?

westend: All good ideas to try next. I feel sure I know what circuit it is on. I have all the fuses identified.

ScottG: Yes, I realized that right after I posted the first note. Thanks.

Another question: Each wire leaving the 12V power panel is a different color. I presume each entire circuit is the same color. Is that a common practice for RV wiring?

This will read through wallboard and even a few inches underground for buried cable.

[RJsfishin]

I would say, if its not a short circuit, its a long one,........in this case, very long 🙂

[Chris_Bryant]

Also keep in mind you could have an open ground to the fixtures.

[FLY_4_FUN]

I have had numerous failures of the switches in several rv's. I think the fixtures were Bargman (sp) and it was cheaper to replace the fixture than try to find just the switch. I wonder if maybe your switch or one of the connectors in the fixture is loose.

Daryll

[fischer]

Call fleetwood the will send you the wiring and plumbing for your coach free have the fleetwood vin number

[westend]

Another question: Each wire leaving the 12V power panel is a different color. I presume each entire circuit is the same color. Is that a common practice for RV wiring?

No, it's not common. More typical is all black or black and white. Count your lucky stars, having color coded circuits simplifies things.

[MrWizard]

papa45 wrote:
Spring Break, last week, the 12V bedroom ceiling lights went out. Fuse is good. Other lights on the same circuit work OK. There is no power to the wall switch. Can't find anything loose on the power panel or converter. I assume something shook loose, but electrical code should not allow any connections that are not located inside an electrical box. I can't guess how the wiring is routed inside the floor and/or walls. Any suggestions?

That is not a short...that is an open circuit, loose or corroded connection, most likely on the negative/ ground connection of the fixture

A short..is a short circuit..current flowing where it is not supposed to
This over heats wires, burns things up, blow fuses first if your lucky

[Bobbo]

There are no common practices for RV manufacture.

Now whether that practice was followed on YOUR RV, don't know.

[papa45]

bpreece: Will that cable tracker work through a floor or a wall, particularly when I'm not even sure where the wire is located?

westend: All good ideas to try next. I feel sure I know what circuit it is on. I have all the fuses identified.

ScottG: Yes, I realized that right after I posted the first note. Thanks.

Another question: Each wire leaving the 12V power panel is a different color. I presume each entire circuit is the same color. Is that a common practice for RV wiring?

[ScottG]

Just a note, what you have is more of an "open" than a short.

[westend]

papa45 wrote:
The RV isn't here right now, but when I was messing with it a couple days ago, it measured something close to 0, less than 0.1V, as I recall.

OK, we could assume that the switch is interrupting the power to the light and continue to diagnose from there but just to be on the safe side, check to see if there is continuity between the wire on the switch and ground. If there is no continuity, you can safely assume that there is an open between the switch and the source of power. If the switch is in a bedroom that is the farthest away from the distribution center, you can assume that power is coming from a circuit close to the switch. Check nearby light fixtures, 12 volt power ports or any other 12V circuits close to the switch. The assumption that the switch obtains power from a nearby 12V circuit would be reinforced if you have just one light circuit or just a couple 12V circuits in the distribution center. You may be able to eliminate 12V power circuits as culprits by identifying those that are powering a single device--pump, thermostat, water heater, etc.

If it proves impossible to find the open in the circuit, you may wish to fish a new wire between the switch and a good source of 12V.

[bdpreece]

Go buy one of these Cable Tracker shut off all power to the coach and hook it up at the light.