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OEM tow wiring mismatch

Discussion in '2nd Gen. Tacomas (2005-2015)' started by Dreyfus, Jun 12, 2011.

  1. Jun 12, 2011 at 8:25 PM
    #1
    Dreyfus

    Dreyfus [OP] Member

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    When I picked up my 2008 prerunner from the dealer he had installed the stock hitch as per our agreement but didn't install the wiring due to time constraints. So he dropped the price $200 and gave me the stock Toyota wiring kit to install myself. So far, so good.

    However, today I found that the directions on the installation sheet show a different configuration under the dash than what my Taco has. The wiring harness itself will plug into the existing unused plug with no problem, but the kit has a converter box which is to be attached to the side of the truck underneath the dash and then plugged into another existing unused plug. Neither the holes for the converter nor the converter plug exist on my truck. :(

    The wiring kit is Toyota, and says for 2005+ year Tacomas. I'm wondering if the converter box is not required on the 2008 and it is provided for the other model years that do require it. As I said, I can install all the other parts without it, but clearly if I need it I'll need a different model converter box because this one won't fit my truck.

    Does anyone have a clue about this?

    2008 PreRunner Sr5 TRD Access Cab - Indigo Ink Pearl
     
  2. Jun 12, 2011 at 10:45 PM
    #2
    BUZZCUT

    BUZZCUT Well-Known Member

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    I just got a plug with wires for my 07. Im kinda wondering why you have a converter box since electric brake controllers are 12 volt.
     
  3. Jun 12, 2011 at 10:55 PM
    #3
    joes06tacoma

    joes06tacoma Well-Known Member

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    Central Coast, CA
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    06 4x4 Off Road Access Cab v6 6spd
    LEER Shell with dome lights operated with 3 way switches, aux backup lights with relay and 3 position switch, modified wiring to compass/temp display and clock to include switch that disables dimming function (poor man's DRL solution), Scan Gauge 2
    Mine had the brake controller on it when I bought it used. There is a single connector behind the driver's kick panel that connects to a harness with four wires in it. That harness is spliced to the harness that came with the brake control. For some reason, there is one additional wire spliced into the stop light switch. Not sure why they had to do that. I haven't towed anything yet, so I don't know for sure that it works, but seems to be a complete install.

    Are you sure that the converter box isn't for the wiring connector at the back of the truck where the trailer would plug in?
     
  4. Jun 13, 2011 at 5:16 AM
    #4
    Dreyfus

    Dreyfus [OP] Member

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    Yes, the diagrams clearly show it plugging into the "P9" connector under the dash and installing it with a preexisting hole there. Neither exist.

    Like BUZZCUT, I have the wire harness that reaches from the back flat four trailer connector to the front unused 4-prong connector that does exist. Also, there's a relay and two 30 amp fuses to install in the electrical box by the battery.

    So why the converter box and do I really need it?

    I just don't want to go through all the trouble of installing everything only to find out I need another wiring kit altogether.
     
  5. Jun 13, 2011 at 9:30 PM
    #5
    Bodete

    Bodete Well-Known Member

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    Eibach springs w/ 5100 Bilstein shocks set to "0", Rear TSB
    Did the dealer give you a 4 pin or 7 pin connector?
     
  6. Jun 13, 2011 at 11:47 PM
    #6
    KellyJoe

    KellyJoe Well-Known Member

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    Sounds like you are installing the wire harness kit for the four pin. I did the exact same thing a couple of months ago on my '08 Prerunner. While the instructions aren't very clear, I'd be willing to bet just about anything that what you need per the instructions is all there. I had to pretty much rip out the lower dash to get to it and stand on my head with my flashlight in my mouth while snaking my hands through a rat's nest of wires. The slot and hole for the bolt to mount the box in question is there. Trust me I almost gave up. I'd offer to send a pic but I don't know if I can get one with it all back together. Everything works perfectly by the way so I can't say if you could do without it.
     
  7. Jun 14, 2011 at 6:44 PM
    #7
    Dreyfus

    Dreyfus [OP] Member

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    Yes, it's the four-pin trailer connector.

    I stopped by our local dealer and he brought up the schematics. He said the kit was right, but the diagram wasn't very good. He said the controller plug and mounting hole was way up in the dash, not down with the rest of the wiring as the instructions indicate.

    I'll have to take another look when I get a chance to crawl up there.
     
  8. Jun 15, 2011 at 10:41 AM
    #8
    reg boulette

    reg boulette Well-Known Member

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    Just did this on my '09....4 pin connector trailer connector. Same harness for 2005 and up.....

    -The converter box goes way higher on the inner wall under the kick plate than you would originally think. Keep looking. It will locate at the top of a 'stack' of square boxes. You will see a threaded hole and two notches in the sheet metal when some tabs fit in.

    -would recommend attaching the 9 pin wiring harness to the converter box before attaching it by screw to the metal wall. The harness connector is nestled in a collection of wiring coming from under the hood to the cab. It will have some various coloured wires attached. To free the wires and allow movement of the harness connector, electrical tape must be removed from the cluster of wires. It is easier if you can remove a big plastic connector holding the wires (and the hood release wire). Although if you rip it out as I did, replacement part is $16.00

    -the 4 pin plug is relatively easier to find. The diagram in the instructions will show the trailer harness wire follows the curvature of the floor (next to where the dummy peddle was before you removed it) Search a bit higher on this curvature and you will find it.
    -I did not take any pictures as I was hanging up side down with a flash light in my mouth. Sorry. Would really help to remove the driver's seat in addition to all the dash/plastic detailed in the instructions. I have no idea about a braking controller as all I need was 4 pin trailer lighting.
    -after all, it worked great. Was having trouble with the T connector set originally bought - weird lighting things happened - so would really advise using the Toyota harness at least for 2009's with the LED tail lights and wiring harness which combines lights and ABS as well as whatever else they stuck on the circuit.
    -don't forget to disconnect your battery before starting work. Your engine and air conditioning will work weird until they relearn their settings.
     
  9. Jun 19, 2011 at 6:12 PM
    #9
    Dreyfus

    Dreyfus [OP] Member

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    Well, I found the plug and the mounting location for the converter box. Like KellyJoe & the dealer said, it was way up in the dash.

    The problem was that there was an unexpected aftermarket remote start box in that space covering the area I needed to get to. Once I uninstalled that and it's wiring I was able to put my trailer wiring in without any problem.

    Everything is hooked up and back together, ready for towing.
     
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