3rd wire in battery box?

Discussion in 'Wiring' started by LaneG, May 20, 2020.

  1. LaneG

    LaneG Member

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    Hi, I'm a tent trailer newbie. Read my intro to get all the details.

    I replaced a broken up battery box on my 2005 Fleetwood Victory. It had the two black and white heavier battery wires and then a third lighter gage wire that wasn't hooked up to anything. I tried to search for the answer already and didn't find anything definitive.

    Anyone know what this is for? Anyone have a wiring diagram?
     
  2. Aladin Sane

    Aladin Sane I'd rather be camping

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    Does your pup have electric brakes? Maybe the light gauge wire powers the break away function of the brakes?
     
  3. Snow

    Snow Well-Known Member

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    Trace it, only way to know for sure. There really isn't specific wiring diagrams for trailers, like there is for cars.
     
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  4. tzmartin

    tzmartin Well-Known Member

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    What color? Does it look like it came original with the camper? Could be a remnant of a 12v mod someone added on.
     
  5. GreyFox

    GreyFox Well-Known Member

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  6. Raycfe

    Raycfe Waterford Ct.

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    Most likely an add on ......... power jack, a light for hitching up, breakaway switch, a power socket that could be anywhere on the camper.
    As Snow replied ............ Trace it for sure ........ label it so you know next time.

    I have never seen a camper wiring Schematic that had a good diagram of the battery connections. Usually they are just interior stuff. And a wiring diagram won't show a wire that someone added.
     
    Last edited: May 20, 2020
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  7. rabird

    rabird Howdy!

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    the wire could be for the breakaway switch that activates the brakes if the trailer becomes disconnected. Likely connects to batt +.
    brake.jpg
    the cable on one end attaches to you vehicle while towing and should pull out the plunger to activate the brakes if the trailer becomes disconnected.

    trace the wire as see where it goes.

    good breakaway primer
    http://popupbackpacker.com/how-to-test-a-trailer-breakaway-switch/
     
    Last edited: May 20, 2020
  8. LaneG

    LaneG Member

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    Trailer3rdWire.jpg Trailer3rdWire.jpg

    By posting my question here. I was hoping for a easy answer. That everyone had one of these third wires and it is universally for such and such. Silly me, huh?

    Thanks to you all for your help. To answer a few of your points...

    1. Yes it does have electric brakes.
    2. It is yellow and black (maybe brown) striped wire. See picture.
    3. It does look like it is original with trailer as it goes into wiring harness like the two bigger ones.
    4. Thanks to GreyFox for the link. There is a lot of good info there. I did find a picture in there for my unit. And it does list a yellow/black wire near the sink and kill switch and pump. But I can't make out exactly what it is pointing to.

    Looks like I'm just going to have to trace it like suggested. But I'll have a look first near the kill and pump switch.

    So you guys have helped and I appreciate it.

    Happy Trails
    Lane
     
  9. Raycfe

    Raycfe Waterford Ct.

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    It maybe a feed to the convertor. I would check the wires in the back of the convertor. Just a hunch.
     
  10. rabird

    rabird Howdy!

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    if its not a breakaway switch wire then you need to make sure you have one!
     
  11. LaneG

    LaneG Member

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    Good idea.
     
  12. LaneG

    LaneG Member

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    Yes, when I get my brake controller wired up. I'll make sure the brakes work.
     
  13. McSkippy

    McSkippy Member

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    You don't need a brake controller to test the breakaway switch.
     
  14. Jimbow

    Jimbow Well-Known Member

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    If your pup comes loose from the TW your controller will also be disconnected. The breakaway switch will lock the trailer brakes and hopefully keep the pup and everything around it safe.
     

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