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4 Pin Trailer Harness

Discussion in '80-Series Tech' started by CDN_Cruiser, Apr 9, 2003.

  1. CDN_Cruiser

    CDN_Cruiser

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    I am in the process of buying a light duty boat trailer, hitch, etc and, in the process of trying to solve my sunroof problems, discovered that my LX450 is actaully wired with a trailer harness (there is a silver lining to every cloud, although it would have been nice if they left the hitch).

    All points seem to be connected, except for a white wire that has a 'raw' end. I did a quick search and it looks like white is ground, which suggests that someone just pulled it off the ground point and stuffed it in the DS rear compartment (with the jack).

    Can someone tell me where to 'exit' the harness on an 80 so that is comes out under the truck? Mine looks like a temp install in that they may have just run the harness through the rear hatch to the trailer.

    Cheers, Hugh
     
  2. yomama

    yomama

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    CDN_cruiser,

    Where is this "silver lining" connection you found, in the inside rear quarter panel? The connection for the trailer wiring should be under your vehicle on the passenger side. The wires in the quarter panel go down to a boot that passes through. You will need a "special" box that is part of the trailering setup, a Toyota part number. This box converts the signals because of two reasons I believe. One being the split turn and brake lights and the second being the negative (hot) so to speak. 12v+ is always appiled to the lights and a ground then provides the completed circuit. If that makes sense? Hard to explain.

    Yomama
     
  3. CDN_Cruiser

    CDN_Cruiser

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    Yoma:

    Thanks :beer:. Mine connection is on the DS inside the storage compartment. There is an aftermarket (I assume given that it has 'Made in Canada' on it) 'box' that is thin, about the size of a pack of smokes. One side of the box is has 'trailer side' the other 'vehicle side' (IIRC) with the wires running into the box.

    Based on your comments (and Toyota's negative ground system), I am assuming that if I ground the unit and test the connections with a DVM I can test to see if it works.

    It also sounds like there is some exit point in the compartment that I push the harness through - I will have a look.

    Cheers, Hugh
     
  4. Brentbba

    Brentbba Former Golfer SILVER Star

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    Hugh,

    If you don't currently have the 4-pin and harness installed their is a company called Hoppy that sells a harness that will plug right into the molex electrical connectors that our LC's have. You just have to order the one for a LC. It's a VERY easy install as their are connectors at both the left and right rear just behind the panels. The panels just pull off with push connectors. On the right side as you are looking at the rear of your LC, there is a rubber gasket accessable from both underneath the body and inside the cavity behind the panel. The wiring harness should be run through there. At least on the factory supplied harness I got when I installed my hitch, there was only one way to plug these things into the LC. It's obvious which connector had to run to the left side as it had a longer wire to run under the carpet at the tailgate. I'm a neophyte when it comes to things like this and it took me all of five minutes to figure out and install it.

    You mention a hanging white wire. Without looking at my LC, couldn't tell you what that is. You may be better off just buying the Hoppy connector and replacing what you currently have. Check out http://www.hitchcorner.com/t_connectors.htm
    Your local automotive store will probably carry them as well. Wished I had know about Hoppy before I replaced my OEM converter in the harness that had gone bad. I bought a generic one from UHaul and redid the molex pin connectors to reuse them to keep the connectors in place.

    You can always buy the harness directly from Lexus. It is available. When I did purchase my Toyota hitch and harness it was a Lexus wiring harness that came with it. Here in the states they wanted $60 for the OEM harness part. Toyota does not list the wiring harness separately. The Hoppy connector is much cheaper.

    Best of luck.
     
  5. bkgiii

    bkgiii SILVER Star

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    Hugh:

    My '96 LX also has the 'factory' 4-wire. It exits from the DS rear storage compartment, runs along undercarriage, and comes out above the hitch frame. My white wire is to ground (Frame ground).
     
  6. Underdog

    Underdog

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    Why does this part say for '96-'97? Is my '94 wiring different or will this work? I'd love to not have to splice into my wiring.
     
  7. Strider

    Strider

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    BK,
    I've got that connector already behind my spare tire on the hitch point toward the front of the bruiser. Is there a plug-in connector that takes those wires to a standard 4 pin trailer on the other side of the hitch? It seems like that assembly would only be about 6 inches long and would either hang or possibly mount to the back side of the hitch.

    Brent, is this ~6" assembly the 'hoppy' you're referring to?

    Matt
    :stupid:
     
  8. Brentbba

    Brentbba Former Golfer SILVER Star

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    The Hoppy harness is a complete wiring harness kit that will just plug right into the existing wiring at the rear tail lights.  There is a small black box about the size of a cigarette package that converts the LC wiring signals to the 4 pin connector.  The harness should come with the 4 pin connector.  All I had to do was cut the rubber grommet open wide enough to push the connector thru to the cabin.  Plug them in and you are done.  I ran the wiring from one side to the other under the carpet inside the vehicle at the tailgate.  The only wires routing out of the vehicle are the ones leading to the pin connector itself.  Good protection would also to get some split loom to put the exposed wires in.  

    Don't know if that helps any.  
     
  9. semlin

    semlin rocker

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    Brent

    I’m interested in where exactly this molex connector trailer hitch harness plug in you refer to can be found. My 93 lc80 has an original factory trailer package but the 5 pin unit, including the Toyota cigarette pack with a 92 build date, is spliced into the rear taillight wiring on the p-s. There is no plug connector I can see but I would love to find one since I need to replace the whole harness and don’t really want to resplice everything..
     
  10. Brentbba

    Brentbba Former Golfer SILVER Star

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    semlin,

    Interesting. When I opened up the rear quarter panels on each side of my '94 there were unused molex connectors as part of the wiring harness going to the rear tail lights. There was only one way to plug in the OEM 4-pin wiring harness on each side.

    You say you have a factory wiring kit. The one I received when I purchased the hitch and harness from Toyota had the molex connectors as part of the wiring harness assembly. Could a PO have not know? I think the wiring kit that Hoppy sells for a LC of our generation is for a 91-94, so your LC should have had them at some point. Again, could a PO have cut them off? Sure made installation of the harness easy. NO splicing or butt connectors requrired.