Afraid to plug in "new" camper

[Hillbilly75]

Just towed my first Airstream home (75 Sovereign) with no problems, and now beginning to explore and see what works/what doesn't. First observation, no brakes. Second, no 12v power to anything. Checked battery, it's probably not good. Reading 9+ volts, and the guy says he tried charging it overnight before I picked it up on Saturday. Third, the univolt has been disconnected, and there is a replacement mounted on the wall. Red and black leads attached to the back of the fuse panel somewhere, "wall wart" plugged in to an outlet above the old univolt, a black wire connected to the ground block of the fuse panel (seems to go toward battery compartment) and a black wire, same size as the other black one, not connected to anything. I suspect it is a ground wire to the battery, as it also goes through a hole toward the battery compartment. I don't see any other ground terminal on the fuse panel, and I'm sure it needs connected somewhere. The last thing I figured out by opening the plug on the umbilical. Two wires are disconnected: trailer brakes and the charge line. My goal is to have everything work pretty much like it did in 75, including having the backup 12v system and ability to charge while in transit. If I knew for sure where that ground wire goes, I would go ahead and try shore power to see what appliances work and what ones don't. The new charger is a Nautilus.

[Jammer]

Welcome

In general I don't give much electrical advice because you really should have a qualified person physically present.

That said, if I am trying to evaluate an entirely untrusted 12v system I would start with a visual inspection, then check for shorts with an ohm meter, then apply 12v DC in a current-limited fashion using an automotive battery charger or something.

120v system should proceed more or less the same way with everything thoroughly checked out with the meter before applying power.

Never heard of Nautilus converters, who knows, it may work fine, but you might be better off replacing it.

[hissilver]

I agree with Jammer. Electricity can be a shocking experience if not done correctly.

[Taylormade]

Pics would go a long way here as well. If you can post what you're seeing, it would help us help you.

[overlander64]

Greetings Hillbilly75!

Welcome to the Forums and the world of Vintage Airstreams!

Originally Posted by Hillbilly75

Just towed my first Airstream home (75 Sovereign) with no problems, and now beginning to explore and see what works/what doesn't. First observation, no brakes. Second, no 12v power to anything. Checked battery, it's probably not good. Reading 9+ volts, and the guy says he tried charging it overnight before I picked it up on Saturday.

When connected to your tow vehicle, you should have 12-volts to coach as well as brakes when the tow vehicle mounted electronic brake controller is operated. With a Vintage Airstream when this isn't the case, the usual culprit is the traierl's umbilical cord. Airstream utilized its own unique wiring pattern for the Bargman connector for many years, and the schematic utilized in the 1970s has a number of differences from the current industry standard both in wire placement and color/function identification. I am attaching a pdf of the original Airstream wiring schematic that may be of help.

Originally Posted by Hillbilly75

Third, the univolt has been disconnected, and there is a replacement mounted on the wall. Red and black leads attached to the back of the fuse panel somewhere, "wall wart" plugged in to an outlet above the old univolt, a black wire connected to the ground block of the fuse panel (seems to go toward battery compartment) and a black wire, same size as the other black one, not connected to anything. I suspect it is a ground wire to the battery, as it also goes through a hole toward the battery compartment. I don't see any other ground terminal on the fuse panel, and I'm sure it needs connected somewhere.

I suspect that your 12-volt power issues are likely related to your Univolt/Power Converter installation or lack thereof. The original Univolt likely contained the 12-volt fuse panel while the new replacement was likely designed for use with a separate 12-volt fuse panel. Some owners keep the original Univolt in line for the fuse panel while the power conversion and charging is handled by the new power converter . . . this can create a very confusing wiring problem that can become dangerous. Should you find this is the case in your newly acquired Airstream, the safest first step may be to install a new 12-volt fuse block (these can typically be obtained from a well-stocked auto parts store or RV/Marine parts store). An Airstream factory service manual may be a good starting point to sort out the 12-volt wiring on your Airstream. Copies of the original Airstream manual may be found at this link (Owners' Manual) -- link (Factory Service Manual). A 9-volt reading on the coach battery would suggest that it is likely time to consider a replacement. You may also want to check the condition of the large, in-line fuses that are usually found in the battery cables themselves.

Originally Posted by Hillbilly75

The last thing I figured out by opening the plug on the umbilical. Two wires are disconnected: trailer brakes and the charge line. My goal is to have everything work pretty much like it did in 75, including having the backup 12v system and ability to charge while in transit. If I knew for sure where that ground wire goes, I would go ahead and try shore power to see what appliances work and what ones don't. The new charger is a Nautilus.

I suspect that a previous owner was probably confused by problems with power to the coach and trailer brake function and disconnected the wires rather than determining that the problem was more likely caused by the way that the Airstream originally wired the Bargman connector. You may find that sorting out the wires in the coach's umbilical (Bargman) connector will solve your issues with brakes/charge functions.

You might find a procedure that I have followed when connecting both of my Vintage Airstreams to 120-Volt AC power for the first time to be helpful. I always turn the 30-AMP circuit breaker off that controlls my RV electrical outlet and then plug in the coach . . . then return to the breaker panel and activate the RV breaker . . . if the breaker trips immediately or heats up noticeably within a minute of applying power, I know that there is a problem in the Airstream's 120-Volt AC setup.

Good luck with your coach!

Kevin

[Hillbilly75]

Wow, thanks for all the information everyone! This is definitely the right place. I tried posting a picture of the Nautilus unit before, but I don't see it here now. I should take some new pictures tomorrow afternoon and give a better idea of what the setup is. The diagrams will be a great help also. Thanks again!

[Hillbilly75]

Some additional pictures of the fuse block, and the one disconnected wire. It does not go to the battery. I traced it under the floor to some sort of aluminum bracket, which is no longer connected to anything.

[Hillbilly75]

Well, I plugged the camper in, turned on the breaker, and the power converter came on! However none of the 12v lights or appliances have power. While I was at it, I decided to try the gas appliances. The stove and wall oven light perfectly, and have a nice hard, blue flame without making any adjustments. I'm still not sure if the refrigerator works. I will try that out today.

[Taylormade]

Ok, now we're talking. In the second picture, what's up with the unplugged ground wire?

Do you have a voltmeter that you can test the power converter's output? Just because it's humming doesn't mean it's working. Check into it. Should be putting out at least 13V.

For the propane portion of the fridge to work, it has to be on level ground. Many newbies assume their fridges don't work only to find out they probably did, and they just weren't level. Don't ask me how I know that.

[ddruker]

I'm with the first poster. I would plan on replacing that converter with something modern - the technology has improved immensely - and it will only cost you about $100.

As far as debugging your 12V system - entirely disconnect the battery, your converter and the lead from your tow vehicle - as in physically remove the wires going to each them from your distribution block - and then apply a new, known good 12V source to your distribution block to begin to test out your 12V system. You need to disconnect all of your sources to make sure none of them is actually acting as a short circuit or power sink.

Last thought - in my airstream, in the 12V system, black wires mean positive and white wires mean ground. I know this is inconsistent across various years of airstreams - just be aware it's possible - I was used to red being positive and black being ground in 12V systems.

[RocketManKen]

Always start checking grounds first. (Well, new battery) Bad grounds will give so many odd symptoms you will lose you mind. Older unit, new to you, just make it an item on list. Check grounds. Locate all of them, take loose, clean them. They may ' look pretty good'. Clean them. You will thank me later. Remember, it is all 12 volt, unless it is 110 of course. Pump, furnace, lights, fridge all 12 volt.

And some things are better left to the professionals. Sometimes the pro's have to be forced to look at grounds. They are pros, you are just some guy with a busted-ass camper. It's the little things that will get ya.

[TG Twinkie]

You need to find out what the black wire goes to. The one that is disconnected on the left side of the fuse panel.
Is this fuse panel still in the old Univolt? If so, it could be going to the Univolt and was disconnected by a PO. The wires labeled "car battery" and " trailer battery are the +12 volt side of the circuit. The shunt (copper bar) is the negative side of the circuit.
If you have a battery charger. Connect the red lead of the charger to the terminal labeled " trailer battery" and the black lead to the white wire on the right had side of the shunt.
A modern battery charger will "crowbar" or shut down if there is a problem. Otherwise it will provide the 12 volt DC power you need to verify that the systems work.
Let us know what happens.

[Hillbilly75]

Taylormade and Twinkie, The black wire goes under a little raised panel in the floor to an aluminum bracket with curved ends on it. (I can imagine it holding a glass fuse, only larger than the ones in the fuse panel.) the wire attached to the other end of that bracket disappears somewhere below. I guess it could be a frame ground, but why would it have been fused? More mystery.

Otherwise, closer look at the new inverter shows that it was originally a battery charger, and had alligator clips on it. It is rated at 10 amps. I'm wondering if it would even power all those lights, fans, water pump, etc, without having assistance from a fully charged battery? Does any of you know what the amp output of the original univolt would have been? I found a replacement univolt from a dealer online. I think theirs are rated at 50 amps. Is there an advantage to going with OE replacement, or would it be better and just as simple to go with something more modern?

[Hillbilly75]

Also, good news on the fridge: I had to reconnect some of the linkage to the interior controls, but it lit right up on the first try. Within a couple hours had frost on the freezer shelf, and the doors even seemed to shut better (they had been kind of warped at the top and bottom, so that they rubbed in both places). Only bad thing was I broke the knob that switches from gas to electric.

[TG Twinkie]

Go with a modern converter like a Progressive Dynamics 9245. You can find many types on eBay.
It was common back in the day to fuse the common/ground side of the battery circuit. But it seems odd, if this were the common/ground side. Why would it come in next to the +12 volt from the trailer and car battery. Can you get a pic of this bracket? It may in fact be a 30 to 50 amp fuse holder.
Your question of the capacity of the old Univolt. In my experience they were 30 amp. That's the size of the fuse going to the trailer or house battery.
In most trailers the black wire is the + side of the 12 volt system.
If you know how to use a VOM, it should be easy to identify. By continuity or reading voltage.

[Hillbilly75]

Well, after a week or two of being distracted by floor patching and leak stopping, I finally got around to trying a new battery. Hooked it up, and heard the teenager shout, "Lights are working!" In fact, everything works, except the radio. So, I've decided the wiring is probably correct. I would say that the 10 amps the charger puts out isn't enough to run even the lights, but probably would recharge the battery between camping trips. I will wait till payday and look for a good unit, like the one mentioned above.

[Hillbilly75]

Thanks for all the good advice everybody. Twinkie, I took your recommendation and got the progressive dynamics with charge wizard. It didn't arrive until the day we left on our first camping trip, so we packed it just in case. Good thing, too! The first night the battery got more and more discharged (we were using the furnace) and the lights started going bright-dim as the battery charger cycled on and off. I was trying to figure out how I was going to come up with wires to install the new unit at midnight, when all I had was a roll of 12 gauge wire. I knew it wouldn't be heavy enough, when I remembered that the old univolt was still there under the bathtub. I fished around with my hands and found the original leads still attached to the old univolt, cut those off as long as I could, and they were perfect. I might have a picture on my phone I can post later. The only thing now (electrical) is to figure out if the water pump works, after I finish the plumbing, and to see why the control panel doesn't work. I haven't gotten around to pulling the fuse on that yet, but two fuses for the pump are good (an inline fuse, and the one on the panel).

[Hillbilly75]

I almost forgot the other good news. The brake wire and charge line had been cut short at the umbilical connector for some reason. I got brave and decided to solder a jumper wire between the connector and the remaining wire on each of those circuits, and they worked! I had suspected that the po disconnected those because of some malfunction, but now I think he just didn't bother connecting them because he didn't have a brake controller on his tow vehicle, and maybe couldn't figure out why the other one seemed to be hot all the time. The brakes are great! Makes driving even easier, and I guess the charge line is ok, or I would know by now.