I had the Palomino Pony open yesterday to replace the water pump, and while I was working on it, I decided to fix what I thought was a burnt out bulb on the outside "porch light".
The new bulb didn't fix the problem, and upon checking, it turns out that both bulbs were fine. I checked the voltage to the fixture, and it showed 12 volts! (I don't remember right now whether it was 12 volts, or the 13 or so volts that the converter would be putting out, since it was plugged in.)
With the bulb back in the circuit, this voltage showed zero.
Today, I checked it again. This time, the trailer wasn't plugged in, so it was just running off the battery. This time, the open circuit voltage was 1.5 volts, and with the bulb in the circuit, it was once again zero volts.
I checked the short circuit current with an ammeter, and it showed 1 mA for a couple of seconds, and then went down to zero. This seems suspiciously like a capacitor discharging: There's not enough current to run any meaningful load, but it will show a DC voltage until it discharges.
Upon closer inspection, it looks like the porch light is fed off the same circuit as the heater. I attempted to turn on the heater, and, indeed, it is also dead.
I had previously assumed that there was a direct connection between the battery and the camper's three 12 volt circuits, with nothing in between other than fuses. But the only explanation I can think of for this weird behavior is that there is some electronics between the battery and the three circuits, and that this electronics is shot in one of the three circuits.
I really won't get a chance to fix this until our next trip. And if necessary, we can live without the heater and light. If my guess is right, then what I plan to do is simply move those items to one of the other circuits.
Here are my questions:
1. Does anyone know for sure whether there's any electronics between the battery and the three circuits? It's an Elixir converter, and yes, I know I should get a more reliable one, since I replaced this one three years ago because of a different, but equally strange, malfunction.
2. Does anyone know which circuit is which on the Palomino Pony? Or better yet, does anyone have a complete wiring diagram? I'm hoping that there is one circuit which operates nothing but the 12 volt refrigerator. Since I've never used the fridge on 12 volts, I'll just swap those two. But if something else is on the same circuit, that will make the job slightly more complicated.
3. Are Elixir converters unreliable? Oops. I already know the answer to that one.