Prius Trailer Wiring Using ModuLite 119176

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Hermit_Congrejo, Jun 9, 2008.

  1. Hermit_Congrejo

    Hermit_Congrejo New Member

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    2008 Prius
    I just finished wiring a ModuLite 119176 Protector in my Prius. I chose this one over the T-One 118308 because of reports of popped fuses, and there were a few posts recommending an "isolated" module. The following is a summary of the installation steps, though I may omit some details.

    Qualifier : In my procedure, you'll note that I spliced directly into the tail light wiring, which means A ) you should be comfortable with splicing wires and B ) you will have to repeat the splicing if you ever replace a tail light.

    To start, I purchased a ModuLite Protector Power Module 119176 and a ModuLite Wiring Kit 118151. I also purchased 5 tap splices from my local hardware store.

    Note : Looking back, I really didn't need to buy the wiring kit, because it's only a 10A fuse (w/ holder), a terminal and a bunch of 12 gauge cable you don't use. You can probably get this stuff at a hardware store. Your call.

    Mounting Location : I mounted mine right next to the battery on the passenger's side. There's a piece of double-sided tape on the unit itself. I affixed it after doing all the wiring. See image below.

    [​IMG]

    Here's a picture of the ModuLite spread out on my back seat. Note that the yellow Left Turn wire isn't long enough to reach the driver's side. So, I trimmed some of the green Right Turn wire and grafted it on to the yellow wire.

    [​IMG]

    Take off all the interior trunk paneling to get access to the battery and tail light wires. A wise man once said that this is a perfect time to check your tire pressure.

    [​IMG]

    I used a multimeter to learn which of the wires corresponds to the tail light, brake and turn signal.

    [​IMG]

    Here are some labeled diagrams, which will probably make more sense to you when the harness is in front of you.

    [​IMG] [​IMG]

    Like I said, I spliced directly into the tail light wiring. I could have spliced into the wiring from the Prius' connectors (what the tail lights plug into) but I chickened out. Here's what the completed wiring looks like.

    [​IMG] [​IMG]

    Now, to provide power to the unit. With the fuse out, wire the ground and positive terminals to supply power to the ModuLite. The installation instructions say to disconnect the negative battery terminal. I didn't and lived to tell about it, but I'm not advocating ignoring the instructions.

    [​IMG] [​IMG]

    After everything's all wired up, replace the fuse and turn on the Prius. Now's a great time to test your work. If you don't have a trailer or it's not convenient to hook it up, there are testing procedures in the ModuLite Instructions for those of you with multimeters.

    The last thing you need to do is replace all the interior stuff, open a beer (don't drive) and admire your work. Good luck!

    [​IMG]
     

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  2. narf

    narf Active Member

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    Vehicle:
    2016 Prius
    Model:
    Four Touring
    I used the same unit. but I cut the wiring to the trailer plug so I could run the wiring through that grommet that's on the sheetmetal behind the bumper. If you intend to route the wiring through the trunk and have it drape across the bumper be careful, I did that on my last prius and the paint on the bumper got trashed from the wiring flapping on the bumper.
     
  3. patsparks

    patsparks An Aussie perspective

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    Sounds like another job for duct tape!!
     
    roflwaffle likes this.
  4. Hermit_Congrejo

    Hermit_Congrejo New Member

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    That's a good call. Thank you for the advice. I'll try using some pipe insulation or something. If that doesn't hold, I may mount the wire harness outside the car.
     
  5. timm

    timm Medical Transport Driver

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    Spring Green, WI
    Vehicle:
    2016 Prius
    Model:
    Four Touring
    I store my wires and plug inside the little rear cubbie when not in use and just shut the hatch on the wire when it is in use. (To the side of the latch, of course)

    After two years of use here in Wisconsin with nasty road salt conditions all winter... the plug still looks like new!
     

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    JerryCS likes this.
  6. Hermit_Congrejo

    Hermit_Congrejo New Member

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    Yeah timm, I took (stole) the idea from your previous posts, as I'm all too familiar with our nasty winters. I plan on keeping mine stowed in the spare tire compartment. Hope you're staying dry out there in Spring Green!
     
  7. timm

    timm Medical Transport Driver

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    Vehicle:
    2016 Prius
    Model:
    Four Touring
    Thanks for caring Hermit! My home and family are fine, but many friends and neighbors are not. I've been helping them get in & out with my boat. We'll be needing lots of volunteers all over Southern Wisconsin when the water recedes.
     

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  8. tochatihu

    tochatihu Senior Member

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    timm - almost up to the light switches eeww!

    Hermit C - please consider sharing yout expertise with the Yahoo priustrailers group.
     
  9. kilo watt power

    kilo watt power Junior Member

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    ? where does the yellow wire from the Modulite connect to the left tail light wire? You covered (great photos) all aspects including connecting the green wire from the Modulite to the green/yellow wire for the right turn signal and all other wires:eek:
     
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