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Daniel 07-13-2019 09:08 AM

12V issues
Hi, my name is Dan, I recently purchased a 68 international Sovereign, when installing the battery, I accidentally shorted the battery to the lid. This caused the DC voltage to drop to 8 volts. I am having trouble finding the DC fuse panel... when the trailer is plugged in to 110 the tail lights come on as well. Anyone know where the DC fuse panel is located?

TheGreatleys 07-13-2019 11:31 AM

If you have the original buzz box converter, your fuses should be inside of that. It should be close to your battery. Follow your battery cables and they should lead right to it.

Daniel 07-13-2019 03:41 PM

Thanks, the battery cables sort of disappeared in the wall, but I didnt think they would go far.

Daniel 07-22-2019 08:40 PM

So, I dont know if this wiring has been modified, but I followed the wires going to the univolt from the battery. No fuses, univolt charger works fine. The other set of feed wires goes from the battery to the Airstream control. The red is fused, (not blown) and the white is not. There is continuity on the red but not the white.

Belegedhel 07-23-2019 08:40 AM

So, when you say "the voltage dropped to 8 volts," do you mean that before the short to the cover, you could put a VOM across the terminals of the battery and it read 12+ volts, but now, even with everything disconnected from the battery, it only reads 8? If so, search no further--your battery is wrecked, go buy a new one.

As far as fuses go, you may have to remove a little panel on the end of the Univolt to expose the DC system fuses. That being said, I don't expect that any fuses got popped when you shorted the battery. You created a very short circuit between the two terminals, if anything, the other (legitimate) circuits in your trailer should have been seeing less potential than normal (unless they were popped in the first place).

Now, the issue with the tail lights should be unrelated to your battery woes. In the umbilical that controls your signal lights and brakes, there is also a charge line that runs back to the battery. This charge line allows 12V from the tow vehicle to go back to keep the house battery topped off while towing. So when you plug into 110V AC, your converter (the Univolt) is getting the 110V and converting it to 12V, and delivering it to the same circuit that that 12V charge line is on coming from the tow vehicle. Somewhere in you wiring, the charge line is touching the tail light wires. Be aware that the wiring pattern in the vintage trailers like yours does not match the modern standard, ie., the pin at position x in your umbilical does not operate the same thing that it does today. You should start out by taking a good look at the plug/umbilical and figuring out which wires go to what (and especially which one is the charge line, and what else it is touching), and making any needed modifications to make the trailer compatible with your tow vehicle wiring.

Good luck!

TomW 07-23-2019 08:58 AM


Originally Posted by Daniel (Post 2263927)
... when the trailer is plugged in to 110 the tail lights come on as well. Anyone know where the DC fuse panel is located?

Many people, while parked, will stick a jumper wire in the 7-pin umbilical connector between the 12v and taillight pins just to get the lights to come on. Make sure that is not your case.

On my '67 there are two, 30-amp fuses mounted on the battery holder: one for the positive wire going to the battery, and one for the negative. I am 99% sure your Airstream's wiring, if still original, should have two fuses also.

Those are the only two fuses in the system. Everything else is protected by self-resetting circuit breakers.


uncle_bob 07-29-2019 06:50 AM


If you started with a brand new battery and accidentally shorted it to take it down to 8V, the battery likely is ok. It's not a recommended thing to do, but it should charge back up. It is worth checking the fluid levels.

If this is a "who knows how old" battery that came with a new to you trailer, it probably worth replacing. That could be with whatever Costco has on sale. If you have big plans for the electrical system, figure that out before you replace anything.

If your trailer is set up with a pair of batteries (which is a good idea) they both get replaced at the same time with the same brand / type.

Also on the list of "stuff" to check into:

How old are the tires?

What shape are the brakes in?

What shape are the hubs (wheel bearings) in?

How are the shocks doing?

Tires are good for no more than 10 years safety wise. They come with a code that tells you when they were made. Batteries *should* also have a date on them. Again, 10 years operated who knows how is too long.

If you still have the Univolt in the trailer, I would replace that as well. It's way past it's use by date ...


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