110 AC but no 12 volt

[seancho]

Hi there. I'm new to the Airstream scene, I'm glad this site exists. I'm dealing with, I believe, a 1966 Sovereign. The electrical system was fine until recently, then it sat for a few months and now none of the 12-volt fixtures or motors work. I'm trying to track down the electrical fault, but my Airstream knowledge is limited.

Plugged into external 110 AC, all the AC outlets work fine. I tested the circuit breaker box and there is current on all four circuits. There is a DC power supply plugged into an AC outlet near the rear service hatch, but it is screwed to the floor in an inconvenient location behind some plumbing and the toilet. Hard to get to. There are 4 DC fuses that look like this:

imgur: the simple image sharer

Left two fuses go to the battery leads, which is disconnected. 3rd fuse is carrying 13 volts and change. Nothing on the 4th one. I assume that since I'm reading DC voltage at the fuse that the power supply is good.

Mice were tearing out insulation and building a nest with it. I'm afraid that they chewed through a wire somewhere. Im just not sure what goes where, and none of it seems too obvious or accessible.

Anyone have any ideas about how to troubleshoot something like this, preferably without tearing out the walls? Thanks in advance.

[rideair]

The fuse inside of your univolt is blown.

It can be found to the left hand side of the toilet looking in from the rear hatch next to the water heater.


Enjoy,

[seancho]

Thanks for the reply. I've got an Intellipower converter. Didn't realize there were fuses on it. However, I managed to get it off the floor and tested it. 13.8v DC output. Same voltage at the fuse. So it's not that.

Yikes, I'm afraid there's a break inside the wall somewhere. Any other ideas?

[Splitrock]

Reattach the grounds.

[seancho]

Interesting. Where are the grounds? How are they attached? Thanks.

[Splitrock]

Originally Posted by seancho

Interesting. Where are the grounds? How are they attached? Thanks.

I posted pictures on this thread.

http://www.airforums.com/forums/f449...nel-74038.html

The white wire screwed to the trailer body is the ground from the converter.





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[seancho]

Ive got continuity from the chassis metal to the power converter, so it seems like the ground is good. There are two wires coming from each DC lead on the converter. Are the extra wires grounds as well? I made sure the negative extra wire leads to frame metal. So I guess it's not a grounding problem. Not sure how to go about further testing...

[Splitrock]

Electricity is like water. One end we have water, one end . . no water. Start at the end that has water. Follow the water. The first point with no water is the last spot to check. Now work back. The problem is between the last place with water and the first place with no water.

I use a no contact voltage tester, a 12 volt jumper light, a small battery charger, and a multi-meter.

#1, I'd make sure the 120 volt is right. Not "looks right" . . . is right. Next I'd remove the converter and do all the wiring diagnostics with my charger with the battery removed. I'd remove the converter and take it out of the trailer, and bench test it. Removing it, forces me to reattach all the connections AFTER I confirm I connect them right, and after I confirm it works on the bench.

I'd remove all the fuses and test all the circuits with the charger. Bench test all the fuses with the multi-meter.