Coach Lighting Short

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?

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

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.

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

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.

Does your meter measure 0 volts on the switch's supply wire?

Chris, I already tried pulling everything on that circuit, but everything seemed solid. Thanks.

If you know which lights are on that circuit, try pulling the closest working fixture to see if there is a loose connection there.

All fuses are good. I even swapped them around to be sure. Wires just disappear down into the wall and into bundles behind the power panel. Nothing is visible in between. No wiring diagram for the coach. I may try to call Fleetwood to see if they can tell me the most likely routing.

Electrical code rules on connections etc. don't apply to 12V circuits (or, perhaps more precisely, the requirements differ greatly). There's no real danger of electrocution from 12V circuitry, so more leniency is permitted.

Are all your fuses verified as good? If so, it sounds like a matter of tracing wires back, unless you have access to a wiring diagram or similar documentation for your unit.