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KerriO · 01-15-2012, 04:54 PM

We've been happily living/traveling in our as for about 6 months now relatively problem-free. We just pulled in and leveled for boondocking and discovered we have no 12v inside the trailer. We have an AM Solar install with a BlueSky charge controller. The charge controller is the only thing inside that has power. That, and the inverter. The light next to the battery disconnect switch doesn't even light up. Outside, the power jack is powered and all of the running lights work. Charge controller shows battery at 100%.
We checked all the fuses on the converter and reset the breakers. Any tips on what we should be looking for or doing?

Al - K4GLU · 01-15-2012, 05:26 PM

How about the battery disconnect switch.

KerriO · 01-15-2012, 05:29 PM

Battery disconnect switch does nothing when pushed and does not light up. It was on and working correctly this morning before we left our last place ( where we were hooked up to 30amp, if that adds any clues).

KerriO · 01-15-2012, 05:31 PM

Quote:

Originally Posted by KerriO

Battery disconnect switch does nothing when pushed and does not light up. It was on and working correctly this morning before we left our last place ( where we were hooked up to 30amp, if that adds any clues).

Also, we did just read another thread that the rocker for the disconnect switch can go bad. We did unscrew the plate and it "looked" fine, but I'm not sure how we'd really tell.

TBRich · 01-15-2012, 05:41 PM

I know I'm not offering any solutions but since the battery reading is good, and your inverter is working (which gets its power from the batteries) it does sound like the 12v power is simply turned off (as opposed to dead batteries), which would be the result of having the disconnect switch in the "save" (or off) position while not on shore power. The light for the battery use/store switch would be off in this scenario...but should come on when you put it in the "use" position to access 12v poser from the batteries. It sounds like the switch might very well have gone bad. If you're up to it you could try to bypass the switch to see if the power is restored...if you bypass the switch and the 12v power comes back on, then it's the switch itself.

Al - K4GLU · 01-15-2012, 05:42 PM

Have no further suggestions beyond maybe a loose connection. Check the battery cables to make sure they're tight and not corroded.

KerriO · 01-15-2012, 05:54 PM

TNRich, all that makes sense. How would we go about bypassing the switch?

Connections all appear ok and definitely no corrosion, at least near the exposed areas.

tsunami · 01-15-2012, 06:13 PM

Check your ground. Especially at the ground bus bar. I had a very similar problem during the winter at Yellowstone. Mine had vibrated loose and just a couple of strands of wire were touching the ground bus so it kind of worked. Take a long wire and connect it to the ground bus and then back to your inverter. Hope this helps.

jdalrymple · 01-15-2012, 06:16 PM

If there are only two wires on the back of the switch simply pull off the wires and touch them together and see of the power comes on.

TBRich · 01-15-2012, 06:26 PM

Yes, what Jeff/Cindy said... OR if there are more than two wires coming into out from the switch, disconnect them and then connect the like wires directly, bypassing the switch.

Of course if this is the problem you will eventually need to put a new switch in, but you will be good to go until you do that. Just tape or otherwise cover the wire connections so they can't touch each other or any metal. Our switch is in the "use" position all the time, since it is always plugged in at home and we never shut the rig down completely.

Gene · 01-15-2012, 06:55 PM

I agree with the previous posts, but your jack works because it is wired directly to the batteries. The running lights should be powered from the tow vehicle.

Sure sounds like the battery disconnect switch, or 12 volts is not getting to the 12 v. fuse panel for some other reason. Do you have a voltmeter that does 12 v. DC? If so, check whether you have voltage coming to the battery disconnect; you'll need to check each lead and connect the other side to a 12 v. ground (the aluminum body should work). If volts in, but not out with the switch in both positions, you have found the problem.

Gene

KerriO · 01-15-2012, 08:28 PM

Thanks all. I realized what a silly question the switch question was after I asked it. The electrical is always our weakest point in terms of knowledge, so when something electrical goes wrong, I go blank. Gene, I knew the voltometer would come into play, and we needed one in our kit anyway, so went to town to get one (plus ice for the fridge and a couple of gallons of water since we can't use the pump... and dinner). We'll troubleshoot more in the morning. Luckily, we're in warm Southern CA right now, so can get through the night w/I power/heat.

zlee · 01-15-2012, 08:31 PM

Oh good, I was thinking you might be sitting somewhere freezing.

KerriO · 01-16-2012, 10:23 AM

Okay, so the switch isn't just simple wires on a switch. It's 5 wires fed into a circuit board. I thought it was more complicated than just a switch!

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When we tested the circuit w/ our new multimeter, assuming we were doing it right -- we disconnected the wire harness from the circuit board and tested each wire-- the white one read as shortz

TG Twinkie · 01-16-2012, 11:04 AM

Can you post a pic of the other side of the board? I see what looks like a pin out for a double pole double throw switch on the back of the board.
When you say the white wire is a short. How are you measuring it? Usually white wires in a trailer are ground/common. The brown wire looks like it should be the +12 volts since it is connected to the center pole of what I think is the switch. Do you read 12 volts between the brown and white wires on the connector?

Gene · 01-16-2012, 11:17 AM

The normal color coding on wires is black = hot, white = common (the other side of the circuit), green or bare = ground. Red is used for a second hot wire in some applications. Brown can be anything.

The colors there may mean black and red are hot in and out; white and brown could be common in and out. All maybes. Brown could be ground and green common. Trace the harness back to where it starts if you can, or locate the other end of it and see where the wires go and that may tell you what is what.

Auto wiring tends not to always follow the color coding that is required in 120 v. wiring, thereby making everyone a little more crazy.

What was hot and what was not?

A short in the white? Take a long piece of wire and connect (jump) at each end of the white and see if things work. If that works, then clip off the bad white wire, connect the new wire at one end and thread it through cabinets and such until you get to the other end. When the new wire goes through holes and past sharp objects, protect it with rubber grommets or lots of good electrical tape.

You could trace the wires through the board and see what is attached to what side of the switch. There are one or two black things on the left side of the circuit board that look like dip switches (switches that slide back and forth). If so, they must do something. Is there any way they could have been pushed the wrong way? There may be a capacitor to the light—that would probably keep it on for a while when the switch is turned off.

The battery disconnect switch confuses most of us. Turn it off and the light stays on, but supposedly will go out after you turn on something using 12 v. So it seems when giving it cursory look, the light means nothing. It looks like no matter which way you press it the light stays on, but maybe will go out after a while. I have seen transformers for some devices with a light that stays on for a while after unplugged. I believe I have read the propane detector, though 12 v., stays powered even if the batteries are disconnected (could one or more wires from the switch go to the propane detector?). So it is the battery selective disconnect switch.

Gene

elfirebob · 01-16-2012, 03:23 PM

KerriO,
All your tests, connections and bypass wires should be under your bed up front.
As pointed out, all leads are focusing on your 12v switch and that same bundle of wires at the switch are also at the solenoid switch that isolates your batteries to your coach.
Start at your batteries where they enter the coach, under your bed. This is where your solar hooks into the system, where the power comes out to the intrior of the coach via the 12v isolator switch. The same five wire bundle you have at the switch near your rear entry door comes out under your bed. Test here to see if it's the switch button or the contact battery switch itself, or just connections.
Remember that testing with bypass wires are ok for a short time during trouble shooting, fix with proper wire size and components.
If you are in the SoCal area, RV supply and AS dealers are fairly close.
Good luck, and ditto on the electrical knowledge, 12v and 110v , add some solar and an inverter, gotta be fun. I have the same componets in our rig.

KerriO · 01-16-2012, 03:26 PM

Thanks all, we are at SW Coaches near Los Angeles right now, as this job seems to be bigger than us. Guy is looking at it right now, and says there's no power to the solenoid, and that some fuse is really hot to the touch when it shouldn't be. I'll keep you posted.

To further make things difficult, our batteries are located in the rear storage compartment, and the storage door doesn't open all the way because of our PP hitch, so he guy has to take the bed platform off to access the battery area and all if its various stuff.

TBRich · 01-16-2012, 05:30 PM

Glad you ended up at an RV place to resolve the situation. Good move. When I saw your picture of the backside/guts of the switch plate I said to myself, "Yikes! That's more than a "switch"!" There are some simple switches in an Airstream, but that is definitely not one of them!

I have a rule: I can only do and can only know so much ... and when I get to the end of my ability, it is time to call in bigger guns ... lest I make it a "worser situation." It works for me every time!

Hope it gets fixed up for you soon and you can be on your way...

KerriO · 01-16-2012, 10:35 PM

TB, so true. And turns out that it was it was not even as simple as a complicated switch. There were two wires that ran near or under the water heater where the insulation had been worn away and the wires were arcing at some point ( scorch marks even). We're in a hotel tonight because they have to continue work tomorrow to tear up the trailer to reach the wired that need repair. Yikes. I'm glad no further damage was done. And the cost of the repair is relatively low considering.