Trailer wiring harness recommendations?

Discussion in 'Gen 4 Prius Accessories and Modifications' started by Danny Troy, Oct 9, 2016.

  1. Danny Troy

    Danny Troy Member

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    I've been towing my jet ski trailer plugging the lights directly into the rear 12v power supply, and leaving the lights constantly on. Not the best solution, but for the short distances I've used it, it's been ok. I just bought a Harbor Freight folding trailer (yet to assemble it) and plan on using it more than the jet ski trailer, so I think it's time to do the trailer wiring properly. The kits I've seen need 12v power from the vehicle's battery, which might make the installation more complicated, since I don't know of a 12v source near the existing wiring harness. Any recommendations on a wiring harness that doesn't need a 12v source, or advice on where I can find a 12v source in the bottom rear of the car?
     
  2. NmIchaels

    NmIchaels New Member

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    hi Danny, I am planning on plugging into the 12v cigarette outlet facing the rear seats, when I use the trailer. I will stow the plug under the velcro flap in the rear seat, and pull it out and plug it in when I am towing. There is a direct path from under that velcro flap to the cargo area. (they call the things under the flap ‘car seat latch anchors, manual page 71). -michael
     
  3. William Redoubt

    William Redoubt Senior Member

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    I have posted in some other threads regarding routing power from the battery up front to the rear bay area. Also, e-trailer has a plug and play kit for the Gen 4 that I ordered, however it was stolen from my front porch. I am still waiting for them to file a claim after 3 weeks, and am fairly disappointed with the results of their service in that area. Amazon now offers it and I will probably dispute the purchase on my credit card and just get it from Amazon.

    Click here for the Amazon link.
     
  4. Danny Troy

    Danny Troy Member

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    Thanks Michael. Sounds like that might be the way to go. I'll have a look and see if I can locate the Velcro flap you mentioned.
     
  5. NmIchaels

    NmIchaels New Member

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    see manual page 71
     
  6. Danny Troy

    Danny Troy Member

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    Just looked at the manual. Didn't check that location in the car yet. Is there any advantage to using that, instead of just running the wire between the 60/40 seat? That's how I route the 12v source to my trailer now. Works fine, unless there's rear seat passengers.
     
  7. Danny Troy

    Danny Troy Member

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    BTW, I just saw a video of a harness installation in a Gen 3 Prius, and they made the harness connection in the rear left compartment, in the hatch area. I know we have access to wiring in the Gen 4 also, but haven't checked to see if there is a harness with connector in that compartment. I know there is a harness connector at the center of the car near the rear bumper. Does anyone know exactly which connector can be used? I would be nice to locate the box with the electronics inside the car, if possible.
     
  8. NmIchaels

    NmIchaels New Member

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    hi Danny, I just saw a video for our 2016, and it shows that three connections need to be made, one on drivers side, one in the middle, and one on the passenger side: (not allowed to post links yet, so):
    etrailer search C56317

    hopes this helps, I think you are way ahead of me, on this, though.

    ps, can any one of you please explain, or point me to a link on how to safely remove the cargo rear panels, behind the lights, right/left?

    thank you,

    -Michael
     
  9. Danny Troy

    Danny Troy Member

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    Yes, that's the adapter I ordered last night, on Amazon. The video doesn't really show where any of the connections are made on the vehicle, and only mentions what each wire is used for. Hopefully someone on the forum has already done the installation and can help.
     
  10. NmIchaels

    NmIchaels New Member

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    Can anyone help me figure out how to safely remove the rear cargo panels behind the lights in the 2016, so I can install the wiring for my new hitch?

    -michael
     
  11. Danny Troy

    Danny Troy Member

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    Do you have the wiring adapter already, or are you trying to tap into the existing wires, which probably wouldn't work? The adapter I ordered has a T-connector, where you just unplug the harness and put the T-connector between the plugs. I'm pretty sure the plug in front of the bumper will work, but I had hoped to make the connection inside the car. My adapter is arriving tomorrow, so I'll check what wiring is in the left side panel, in the hatch area. I'll also check to see if there is a similar removable panel on the right side, although I don't remember seeing it.
     
  12. William Redoubt

    William Redoubt Senior Member

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    Most likely the t-connector fits at the tail light assembly, not under the car. Both panels are removable. I know on the left there are some screws under the pylons for the privacy cover. It's all pretty simple, I think. The only "real" wiring to do is to connect the hot wire and the ground.
     
  13. Danny Troy

    Danny Troy Member

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    Yes, my adapter came today and I see there are a lot more connectors than I anticipated. Looks like one for each side, and one for the connector at the bumper, which is accessed from the bottom of the car. As mentioned, I'll use the rear seat 12v receptacle for power (+ & -). I'll tackle the installation in the next few days and report back.
     
  14. NmIchaels

    NmIchaels New Member

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    Danny, update please, especially how to remove the panels to access the wiring.

    thanks,

    -michaelN
     
  15. Danny Troy

    Danny Troy Member

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    Michael, the instructions linked show the entire procedure. You basically remove the rear panel, by removing the two hold-down loops, and pop off that piece (try not to destroy the plastic tabs). You also need to remove a screw from each side (and one again try not to destroy the tabs there either). I damaged several of the plastic tabs, but they weren't so damaged that I couldn't re-use them. This is from memory, so you're better off using the instructions, than listening to me! Here's a link to the PDF from Curt: https://www.curtmfg.com/masterlibrary/56317/installsheet/CME_56317_INS.PDF
     
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