Where/how to look for a short/broken connection

[gwinger]

Simple to check that switch. Remove the wires and put your OHM meter across the terminals. In one postion it should show "0" and the other infinite. Or measure the voltage across the terminals. Switch off 12v switch on 0 volts.

 

[bigbAZ]

Simple to check that switch. Remove the wires and put your OHM meter across the terminals. In one postion it should show "0" and the other infinite. Or measure the voltage across the terminals. Switch off 12v switch on 0 volts.

I was reluctant to suggest that as I've seen badly pitted high current contacts show continuity and even pass a small bit of current but fall on their face as soon as any meaningful load is applied. It's a good starting point though as a negative test would confirm it's not closing at all, but a positive test I would take with a grain of salt.

 

[gwinger]

I was reluctant to suggest that as I've seen badly pitted high current contacts show continuity and even pass a small bit of current but fall on their face as soon as any meaningful load is applied. It's a good starting point though as a negative test would confirm it's not closing at all, but a positive test I would take with a grain of salt.

If the contacts are that bad, you probably will not see 0 ohms, or it will fluctuate. Measuring the voltage across the terminals may be a better test. The switch will be under load.
That's also one way to check for a bad fuse.
As far as a meaningful load, there are not many devices that draw high current.
That's a 75 amp switch.

 

[gwinger]

One other thing you mentioned is the battery reading 12 volts after charging and holding that reading the next day with the wires off. You may be reading a surface charge. As soon as a load is applied, the battery will die.
You could take the battery to an auto parts store where they can do an actual load test on it.

 

[Kirk]

If you have 12V power when connected to shore power, that has to come from the converter, if the battery is not supplying it. That would explain things if all of the 12V worked from shore power. Since the refrigerator doesn't but everything else does, that would make me believe that you have a separate problem with the refrigerator. If your fresh water pump, lights, and the furnace all work from shore power it would seem that way. I would trouble shoot only one problem at a time.

A couple days ago the battery itself was reading around 8v, I left it on a trickle charger over night and it charged up to around 12v.

A wet cell battery is considered to be fully discharged when the voltage reaches 10.5V. To accurately measure the battery voltage, one of the battery posts should have all wires removed and then by measuring between them you will get accurate battery voltage. Have you checked the electrolyte level in all of the cells? If they are low that will reduce the amount the battery can hold, even when charged to 13+V.

There's a 40amp fuse the a black rubber housing (seen in the background of the pic) which goes to the tongue jack.

Did you test the jack to see if it will work from the battery, or from the converter/shore power?

The multimeter beeped but also when I checked opposing polarities. (From the replies I see, I guess that would give me a false short reading as it could be caused by other things connected to the circuit.) That being said, would resistance still be zero with my janky workaround?

To know what a beep from your meter means we need to know a lot more about the meter that you have. While I have been a service tech for years, I have no idea what a "false short" might be. What I can tell you is that for a wire or a fuse to read continuity it should show 0Ω on the meter, or very close to that. A short circuit would be for some point in the circuit to measure 0Ω where there should be some resistance or even infinity.

 

[Kirk]

I really want to solve this soon as we are camping next weekend

In looking at the pictures that you posted, you have a WFCO 8900 series distribution panel that includes the converter, which can be seen below the circuit breakers. As such, the positive post of the battery should be connected to a common point with the positive output from the converter, and I suspect that the two black wires at the bottom of the fuse panel are one from each of those sources. Here is a trouble shooting chart for the WF-8900 from WFCO.

 

[gwinger]

If you have 12V power when connected to shore power, that has to come from the converter, if the battery is not supplying it. That would explain things if all of the 12V worked from shore power. Since the refrigerator doesn't but everything else does, that would make me believe that you have a separate problem with the refrigerator. If your fresh water pump, lights, and the furnace all work from shore power it would seem that way. I would trouble shoot only one problem at a time.

A wet cell battery is considered to be fully discharged when the voltage reaches 10.5V. To accurately measure the battery voltage, one of the battery posts should have all wires removed and then by measuring between them you will get accurate battery voltage. Have you checked the electrolyte level in all of the cells? If they are low that will reduce the amount the battery can hold, even when charged to 13+V.

Did you test the jack to see if it will work from the battery, or from the converter/shore power?

If you have 12V power when connected to shore power, that has to come from the converter, if the battery is not supplying it. That would explain things if all of the 12V worked from shore power. Since the refrigerator doesn't but everything else does, that would make me believe that you have a separate problem with the refrigerator. If your fresh water pump, lights, and the furnace all work from shore power it would seem that way. I would trouble shoot only one problem at a time.

A wet cell battery is considered to be fully discharged when the voltage reaches 10.5V. To accurately measure the battery voltage, one of the battery posts should have all wires removed and then by measuring between them you will get accurate battery voltage. Have you checked the electrolyte level in all of the cells? If they are low that will reduce the amount the battery can hold, even when charged to 13+V.

Did you test the jack to see if it will work from the battery, or from the converter/shore power?

That's why I mentioned a load test on the battery. It can read 12 volts while sitting and die as soon as a load is applied
I ride a motorcycle and I can actually load test the battery by using the starter and watching the voltmeter.
By keeping the throttle wide open, the bike will not start. If the voltage drops from 12.5 volts, normal, to below 11 volts, the battery is toast.
My wife's car would not start and the battery showed 12 volts. As soon as she hit the key, it dropped to 8 volts.

 

[Kirk]

You might find something helpful in the WFCO video collection on the customer support pages. They also have a customer service phone number. 877-294-8997

If it were me, I would lift the negative lead from your battery negative post, effectively removing it from the circuit and find out why the refrigerator doesn't work from shore power when everything else does. Then you can look to the battery and get it load tested or replaced as needed, or deal with a bad battery isolation switch. If you want to use the RV this weekend, you could do so just fine if the refrigerator is working by precooling it from shore power before you leave and then just keep the door closed until you arrive and connect to shore power again, and then worry about the other problem when you get back.

 

[snipsnap]

Hi everyone,

Thought I'd share an update. It looks like it was that push/pull switch but not 100% sure. I took the panel off to access the switch and played around with the cables/switch; just inspecting everything. Low and behold everything started working again. Maybe a loose wire/connection in the switch? Who knows but I'll buy a replacement just in case. Thanks again for taking the time to help out. Much appreciated.

 

[Larry N.]

Glad you seem to have found the fix -- and thanks for getting back to us with the apparent solution.

 

[Joe Granger]

1. Take another look at the battery, 12 volts is NOT charged, 12.7 after resting is charged (assuming lead acid). You can't assume the battery is OK just because it's only a year old, if it was allowed to get to 8 volts and left that way it could be damaged/failed. You could temporarily swap it for one from your car/truck to see if maybe there is a battery issue.

2. Is there a battery switch in the RV? Battery switches and their associated relays can fail. If the battery swap from #1 doesn't reveal anything try running a wire directly from the battery + to the converter + battery terminal. If still no power with a verified good battery next do the same with the battery negative.

The above process of elimination steps will greatly speed up the troubleshooting as you won't be wasting time on stuff that is good and it will lead you right to the problem area. You only have 3 basic sections, battery, converter and wiring/switch/relay between them. Find out what it isn't and you will be left with what it is.

Thanks for the info...tech at Camping World told me to do the same procedure. I have the same issue with my '81 Fleetwood Wilderness. So I bought some 6 gauge wire and will connect batteries (I have two 12s with two sets of connections) directly to converter.

 

[gwinger]

Thanks for the info...tech at Camping World told me to do the same procedure. I have the same issue with my '81 Fleetwood Wilderness. So I bought some 6 gauge wire and will connect batteries (I have two 12s with two sets of connections) directly to converter.

You can do that for a test, but I wouldn't leave it that way. You need some type of protection between the battery and converter. If the battery shorts or you accidentally short the battery + wire to ground, you may fry the converter.

 

[OldWEB]

Thanks for the info...tech at Camping World told me to do the same procedure. I have the same issue with my '81 Fleetwood Wilderness. So I bought some 6 gauge wire and will connect batteries (I have two 12s with two sets of connections) directly to converter.

Post a picture and the make/model of the converter for guidance... unless you are sure where to connect it to.