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Wiring at rear for brake, and running lights.

Discussion in '1st Gen. Tacomas (1995-2004)' started by bean dip, May 5, 2021.

  1. May 5, 2021 at 12:25 PM
    #1
    bean dip

    bean dip [OP] Member

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    Hi all-

    Just finished putting a trailer hitch on my '03. Now need to wire in a 4-way plug for lights.

    Does anybody know the details of the rear wiring harness (wire colors vs function)?
     
    Last edited: May 9, 2021
  2. May 5, 2021 at 12:44 PM
    #2
    Black DOG Lila

    Black DOG Lila Well-Known Member

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    Virginia
    Vehicle:
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    Stock. EZ pass.Dump pass.Inspection sticker.Convict printed lic.plates.FG cap.
    Check Amazon for plug in wiring harness for Tacoma.
    It has the module.
     
  3. May 5, 2021 at 12:51 PM
    #3
    OpeCity

    OpeCity Well-Known Member

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    Long Beach, CA
    There’s a plug and play curt harness for like $30. Do that, stay legal

    heck, for another $10 or so you can get the round plug option like I did and run a charge leg back there
     
    Last edited: May 5, 2021
  4. May 5, 2021 at 12:55 PM
    #4
    frizzman

    frizzman Well-Known Member

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    OME 2.5,Tundra 17s,Falken Wildpeak AT3W hitch w/ 7-pin, ARE cap, JVC HU w/BT, HID/LED lights
    what the previous two posters have said, there is a plug'n'play solution from a few vendors that require no splicing or wiring, just a screw on the frame for the ground wire.

    https://lmgtfy.app/?q=2003+tacoma+trailer+wiring+harness

    first option: https://www.amazon.com/Hopkins-43315-Simple-Vehicle-Wiring/dp/B0002Q7ZKK
     
    Seagull233 likes this.
  5. May 5, 2021 at 3:52 PM
    #5
    Wyoming09

    Wyoming09 Well-Known Member

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    Townships need ticket revenue go with not having turn signals !!

    If you get a officer having a bad day and he puts your vehicle out of service things can get expensive.
     
  6. May 5, 2021 at 4:08 PM
    #6
    Actionjackson

    Actionjackson Well-Known Member

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    I have been through 2 of the curt harnesses. They seem to last a couple years then get some kind of an internal short and you don't get tail lights but the brake lights still work. I just remove the harness and put a new one in. I bet others on here have had the same situation because I think it is a know problem with these. I don't have any better solution as I tried to find a higher quality harness but could not.
     
    frizzman likes this.
  7. May 5, 2021 at 6:09 PM
    #7
    frizzman

    frizzman Well-Known Member

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    OME 2.5,Tundra 17s,Falken Wildpeak AT3W hitch w/ 7-pin, ARE cap, JVC HU w/BT, HID/LED lights
    yeah the cheap diodes or whatever inside usually go bad in our northern regions. maybe not so much in the southern dryer climates but I've had 3 or 4 so far on mine
     
  8. May 6, 2021 at 2:47 PM
    #8
    RysiuM

    RysiuM Well-Known Member

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    Was Golden State, now Poland EU
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    1995 4x4 LX Ext Cab, I4 2.7, MT, 335K miles
    DD Deck+backup camera, LED DRL, All LED except H4 Hella
    Some time ago I bought something like that of Amazon and installed in my truck. The plug'n play is great as I could use the "extension" to plug additional things (backup camera, camper stop light), without splicing into original wires. I used it only once for towing when I rented a wood splitter from Home Depot. After that I bough 5th gen 4Runner with factory installed trailer connector, and Used this truck for towing stuff.

    In Poland the 4-wire trailers are not legal, so the module is useless for me but it is still working and not causing any problems in electrical - and I have it almost 10 years now.

    Now looking back I think that these cheap adapters are dumb. Bulbs in trailer are using original wires, switches and fuses from truck's lighting. Any short in a trailer will blow the fuse in the truck. All trailer adapters available in Poland connect to vehicle lighting only to power micro relays. Trailer lighting is powered by separate "main power wire" with it's own fuse and connected directly to the battery. Something like that I will install in my Tacoma when I get it prepared for towing again.
     
  9. May 6, 2021 at 6:04 PM
    #9
    Seagull233

    Seagull233 Well-Known Member

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    BMW seats, OME Suspension, CBI and NWTI plates front and rear, 13,000 winch, LED light bars, Ham Radio, topper with roof rack added, stainless exhaust, 2nd battery, inverter, sound deadener
    What seems to go bad with mine was the box part, where five wires go in and 4 come out. When mine went bad, I bought a generic box (not plug and play, and spliced on the plugs from the Curt harness. It was a much cheaper option, as I recall.
     
  10. May 7, 2021 at 10:22 AM
    #10
    frizzman

    frizzman Well-Known Member

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    OME 2.5,Tundra 17s,Falken Wildpeak AT3W hitch w/ 7-pin, ARE cap, JVC HU w/BT, HID/LED lights
    I did the same thing, only I got the generic one from Hopkins that worked with LED lights (on my trailer) and cut/joined it to the clips. This one also had a separate "power" wire that ran to the battery and I added an in-line fuse.
     
    Seagull233 likes this.
  11. May 9, 2021 at 7:17 AM
    #11
    bean dip

    bean dip [OP] Member

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    Thanks all, for the suggestions.

    I went ahead and opened up the wiring loom under the bed, right behind the license plate and found this:



    Probed the five wires and found the following that I'll offer for those that may wonder down the line:

    ground: white with black stripe
    running lights: green
    brake lights: green with white stripe
    right turn: green with yellow stripe
    backup: red

    Thanks again.
     
    Last edited: May 9, 2021
    crazytacoman likes this.
  12. May 9, 2021 at 10:27 AM
    #12
    frizzman

    frizzman Well-Known Member

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    OME 2.5,Tundra 17s,Falken Wildpeak AT3W hitch w/ 7-pin, ARE cap, JVC HU w/BT, HID/LED lights
  13. May 10, 2021 at 3:55 AM
    #13
    Wyoming09

    Wyoming09 Well-Known Member

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    Those 4 pin plugs are a pain I only install 7 pin plugs no problems
     

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