12v Power Not Working

Discussion in 'Wiring' started by Ryan Graham, Apr 16, 2018.

  1. Ryan Graham

    Ryan Graham New Member

    Mar 12, 2018
    I purchased my first camp trailer this year (2010 Coleman Santa Fe) and just went out on my first trip this past weekend. I purchased a new battery and had it on the charger up until the time I left. I got camp all set and went to turn on a light and check that the heater was working because I expected a cold night. The lights would not turn on at all. I started testing other electrical in the trailer and just no power at all.

    I pulled out the multimeter and tested the better, which was at 13.05v so to my knowledge I was super topped off on power. I confirmed that my connections were on the battery correctly and flipped the breakers off and back on, still nothing. I checked to be sure the fuses all looked good and they looked solid. The galley was up so the kill switch was not the issue, unless during the drive the switch decided to go bad. During the drive I encountered some snow and salty roads so the ground wire seemed a bit corroded so cleaned off the connection and tightened the connection, still nothing.

    When I was at home getting ready I had the trailer plugged in so everything was working. Previous to that I used the trailer on battery power not more than two weeks ago. The reason I ended up with a new battery for this trip is because I had some of the family over and the kids were out playing in the trailer and left the lights on all night. When I got back to the trailer the alarm was making a terrible sound and the lights were completely off but still switched to the on position. I switched off the lights and the sound went away. I assumed that battery was toast so I'd get a new one for the trip. Obviously something else went wrong there.

    Any ideas on what could have happened and how to fix it? Are there fuses somewhere else that could have blown or kill switches that could have been tripped and need to be reset?
  2. joet

    joet Well-Known Member

    Mar 16, 2011
    Elkins WV area
    There should be a fuse close to the battery positive on a wire going towards the rear.
    flipping the breakers will not do anything. The breakers for for 120vt power. (shore power)
    Ryan Graham likes this.
  3. Snow

    Snow Well-Known Member

    Jul 19, 2007
    Just to confirm the white wire at the battery goes to negative ?
  4. jmkay1

    jmkay1 2004 Fleetwood/Coleman Utah

    Oct 10, 2013
    Northern Virginia
    I had the same problem. Not sure if this is your issue but I discovered I had a short in the battery harness that attaches the battery to the camper wiring. In my case the wires were pulling out of the little plastic connector. I bought a new battery harness from Colemanpopupparts.com and the fuse that went because of my short and everything worked.
  5. roybraddy

    roybraddy Well-Known Member

    Mar 23, 2016
    King George, Virginia
    I always look for the symbols stamped on the battery case to be sure I have the FRAME GROUND CABLE going to the '-' or NEG identified terminal. In the RV WORLD this wire should be a WHITE CABLE and the +POS positive terminal should be a colored cable usually BLACK etc... I have also seem all cables WHITE COLORED but the cables that are for POSITIVE CONNECTIONs have a colored stripe down the wire.

    Sometimes the battery cables follow the automotive color sequence being RED for Positive and BLACK for frame grounds. This is why I also also look for the stamped in +POS or -NEG on the battery case to just be sure... It is not uncommon to find something like an automotive FM radio wiring plug using RED for positive and BLACK for ground will be added to a RV terminal setup and you will find a RED CABLE on top of a BLACK CABLE lug connection. This makes the old timers turn over in their graves hehe...

    Also a fully charged battery should read around 12.6-7VDC. The 13.0 you was reading may have been a static charge from being just charged. If you wait a few minutes this should drop down to 12.6-7 if it was fully charged.

    I check my batteries with a multimeter all the time. Without shore power connected I like to see 12.6-7VDC across the battery terminals. Then I will connect up to Shore Power or Generator and I want to see the DC Voltage across the battery terminals jump up to 13.6 VDC or higher depending on what charge state the controller/charger is doing. My setup can go as high as 14.4VDC. This tell me I have a good connection from the battery terminals to the converter/charger connections. Between the Battery terminals and the Power Distribution Panel 12V connection there is a high wattage fuse in-line and also some REVERSE POLARITY fuses on the the Power Distribution panels or charger board that may have blown on you disconnecting the Battery from the Charger. You also may have a DISCONNECT BATTERY SWITCH in the circuit as well which may be in the OFF-Position...

    The ceiling lights in the trailer are 12VDC is also another item you can look at to tell if the battery is connected without shore power being on. Battery not connected for some reason or failed (run down) if you are 'NOT' on Shore Power or Generator and turn on your ceiling lights. Ceiling lights should come ON...

    Having my handy multimeter around all the time keeps me out of trouble hehe...

    Roy Ken
  6. Ryan Graham

    Ryan Graham New Member

    Mar 12, 2018
    Correct, the white is on the negative terminal.

    I'll have to give the fuse a look.
  7. jnc

    jnc Welcome from New Hampshire

    I would check the galley switch. They are prone to failing at the most inconvenient times.
  8. theseus

    theseus Centerville, OH

    Feb 6, 2007
    Centerville, OH
    I assume it is a WFCO power center. If I were you, I'd just buy a bunch of new fuses and replace the ones in the power center, especially the two for the battery. One is a reverse connection fuse, and the other one is the main DC fuse that powers the block. I know you checked them but it doesn't hurt to replace them.

    You can check fuses with your multimeter set to continuity (Ohms). It should beep if it is a good fuse.
  9. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

    Jul 18, 2013
    Thornville, OH
    The good news is with 13.05 volts still in the battery you don't have a short, or you would have drained the battery. You have a missed wired battery, an open, open fuse, high resistance at a connection or the safety switch is not engaging.

    Use your volt meter and see if you have voltage from the battery at the converter between the converter in wire and ground.

    I would check the fuses at the battery and the converter and the wiring to the battery. Sometimes at the battery there is a small rectangle shape metal auto fuse

    The standard wiring to the battery of a camper is white on the negative and black on the positive any other colors you need to figure out.
  10. Ryan Graham

    Ryan Graham New Member

    Mar 12, 2018
    Is it a good idea to have an extra switch on hand? I can't imagine they go out that often, but if that's a common thing to go out I'd rather have one ready to go.

    I tested the switch for continuity and it's good to go.
  11. Ryan Graham

    Ryan Graham New Member

    Mar 12, 2018
    I did this last night and found that there was a fuse that went bad, but looked fine. I'm going to pop by the store today and get some new fuses. Hopefully this is the issue and simple fix!
  12. jnc

    jnc Welcome from New Hampshire

    It is worth having on hand for when it does go. I had to jump out mine 3 hours from home.
  13. Ryan Graham

    Ryan Graham New Member

    Mar 12, 2018
    Well, although the 20 amp fuse for the battery didn't look blown...it sure was. Always test with multimeter, lesson learned.

    One last followup question; when I inserted the new fuse it sparked. Should the battery be disconnected when taking fuses in and out? I'd hate to fry something, but also could be overthinking.
  14. SteveP

    SteveP Well-Known Member

    May 21, 2015
    If you disconnect the battery it will spark when you reconnect, the camper has parasitic draws on the 12 volt system. If it fries anything it will be the new fuse, and then you know you have another problem to find.
  15. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

    Jul 18, 2013
    Thornville, OH
    Alway good to have extra fuses for all the fuses that the camper has. Never know when you are going to be in BFE and you blow a fuse.

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