Forum Discussion

mleekamp's avatar
mleekamp
Explorer
May 31, 2019

"Cut" wires under hood of new Class C Ford chassis?

I have a 34 foot 2019 Jayco 29XK on a 2018 Ford V10 E450 chassis. Under the hood, there are about a dozen wires that look "cut" and are sealed with heat shrink on the end, zip tied to a wire harness. They are not used to my knowledge and I wonder what the heck they are for.

*Sorry, I can't post a pic I'm at work and don't have a pic right now.

I'm actually installing the Invisibrake on my Jeep dinghy and am ready for the last step -- the dash indicator for the RV. Point is, I'm wondering if those wires would help vs. running more wire...just don't know why they are there.

General ideas? A test light helps, I know, but don't even know where they run off to.
Class C
  • carringb's avatar
    carringb
    Explorer
    Jun 01, 2019
    YC 1 wrote:
    Bryan, that is amazing information.

    Are you aware of any wires under the dash that would be used for a trailer brake controller? If there is one pre-wired that can be used to send the signal forward from the toad. This may help the OP.


    Yes. I had assumed you already utilized those for a brake controller, so I didn't mention them.

    Your trailer brake wiring is behind the stock coin holder. Of course, in a motorhome, it may have already been turned into another switch panel, but the connector will still be back there.



    You'll need a pigtail here as well, but eTrailer sells this one. You'll want to connect to the Blue wire, as this is the pass-through wire to the 7-way plug in the back.

    Here's a good video showing how to get to that that connecter:
    https://youtu.be/PCtUMFtuqqo?t=55
  • YC_1's avatar
    YC_1
    Nomad
    Jun 01, 2019
    Bryan, that is amazing information.

    Are you aware of any wires under the dash that would be used for a trailer brake controller? If there is one pre-wired that can be used to send the signal forward from the toad. This may help the OP.
  • Chum_lee's avatar
    Chum_lee
    Explorer
    May 31, 2019
    And one of the nice things about having those dead end wires (where ever they are) is that if you ever need a short piece of automotive grade wire in a pinch, you can remove a portion of the cut end and use that with little fear of damaging anything else. Just remember that they are there.

    Chum lee
  • carringb's avatar
    carringb
    Explorer
    May 31, 2019
    D.E.Bishop wrote:
    Just a note to "carringb", that address you gave just does not work. I'm not a IT guy and I don't know if there is some way to copy and paste it so it works. There is, however, a great little tab to put a link in a post that does allow dummys like myself go to referenced addresses.


    Thy it now. Here's the full text url if it will doesn't work:

    https://madocumentupload.marketingassociates.com/api/Document/GetFile?v1=4391972&v2=071818011525&v3=60&v4=623ada640f9cf49e555ab6b487c75a53324c1e0752189b6ef9b968ae&v5=False
  • naturist's avatar
    naturist
    Nomad
    May 31, 2019
    Every vehicle manufacturer offers options on every vehicle. Wire and connectors are really cheap, it's the finished wiring harness that is expensive, so to save money, they make just one wiring harness for every vehicle of a given model, instead of making 375,000 different ones for every possible combination of options. The savings are substantial, and it leads to nearly every unit that comes off the production line having wires that go nowhere, depending on what options are installed and not installed.

    So, go look under the hood of any of them, you'll find cut off wires dangling here and there. Don't worry about it, it just means that there was an option for something you don't have.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    May 31, 2019
    D.E.Bishop wrote:
    Just a note to "carringb", that address you gave just does not work. I'm not a IT guy and I don't know if there is some way to copy and paste it so it works. There is, however, a great little tab to put a link in a post that does allow dummys like myself go to referenced addresses.

    Click
  • D_E_Bishop's avatar
    D_E_Bishop
    Explorer
    May 31, 2019
    Just a note to "carringb", that address you gave just does not work. I'm not a IT guy and I don't know if there is some way to copy and paste it so it works. There is, however, a great little tab to put a link in a post that does allow dummys like myself go to referenced addresses.
  • mleekamp's avatar
    mleekamp
    Explorer
    May 31, 2019
    Thanks. Yes, I'm installing as it says....it does say "if wires are run front to back of the motorhome, use that wiring. Otherwise install new wire from rear to front."

    Everything works (lights, invisibrake) right now...the dash indicator on the motorhome is my last step before a true test drive.

    I suspected as you said that "probably not connected to anything". Just wondered if anyone knew for sure.
  • carringb's avatar
    carringb
    Explorer
    May 31, 2019
    The blunt-cut wires you are asking about are for the PTO and elevated idled. So it you wanted to add an engine-driven air compressor, or utilize high-idle for faster battery charging or using the chassis A/C while parked, these are the wires you'd connect. They also contain the pass-through wires for the factory up-fitter switches, but most RVs re-purpose that knock-out panel for their own switch panel.

    There is also a pass-through harness. This is near the blunt-cut wires and has a 4-pin connector. You can cut the connector off, or buy an "aftermarket up fitter" pigtail from Ford. This pass-through connector goes to the rectangle plug near the steering column inside the van.

    https://madocumentupload.marketingassociates.com/api/Document/GetFile?v1=4391972&v2=071818011525&v3=60&v4=623ada640f9cf49e555ab6b487c75a53324c1e0752189b6ef9b968ae&v5=False
  • DownTheAvenue's avatar
    DownTheAvenue
    Explorer
    May 31, 2019
    Manufacturers assemble vehicles with parts that are used across many models. That same wiring harness could be used on a model that has features not available on your vehicle and the wires would be connected to support those features. It is probable they are not connected to anything on the other end either.

    Your best bet is to install the braking system exactly like the directions say.

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