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2012 wiring change?

Discussion in 'Towing' started by jimilivz, Jun 3, 2012.

  1. Jun 3, 2012 at 6:30 AM
    #1
    jimilivz

    #1
    jimilivz [OP] Member

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    Looking to add the Toyota tow harness to my 12 rc 4X4, but the partsman says they only make one, pt725-35120, for models equipped with drl (daytime running lights), which mine does not have. I put kit #
    $153 08921-04960 Towing Wire Harness
    08921-04960 on my 2008 rc 4X4 with no problems. It's a great upgrade to the wiring. Anyway, I found a wiring diagram of the 2012 tow harness: 12tacotrlr.jpg
    It appears that there is an input to the relay from the drl. Any electronics guys out there with advice on how to make it work?
     
    jimilivz, Jun 3, 2012
    #1
  2. Jun 4, 2012 at 5:58 AM
    #2
    knucklehead

    #2
    knucklehead Well-Known Member

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    Jeff
    Ottawa
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    Hitch, nav header
    DRL shouldnt play any part in trailer wiring. at all.

    I'm not certain what you are asking about? Does the trailer wiring, in general, not work? Or are you trying to get some function out of the DRL input?

    Assuming that the issue is that the trailer lights are not working...

    Without a diagram for the magic box, it is hard to tell what it is wanting to do with the DRL circuit, as a guess, perhaps it is an "either/or" setup where it requires either the tail light input or the DRL input.

    You should try switching the headlights on and seeing if the trailer lights work that way. You can also try applying +12 volt to the DRL input with the headlights off.

    If it works with the headlights on as well as with the headlights off + DRL tied to +12, then you can add a relay to control the DRL input as REVERSE from the tail light input, i.e., run the coil on a relay off the tail light input signal, +12 to common, DRL to "normally connected". You will need an SPDT relay or an SPST-normally-connected (the latter is very uncommon and could be hard to find).
     
    knucklehead, Jun 4, 2012
    #2
  3. Jun 4, 2012 at 6:29 PM
    #3
    jimilivz

    #3
    jimilivz [OP] Member

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    My question is: If I spend $150 to get the trailer harness from Toyota, will it work with my truck, even though it does not have drl? The Toyota partsman says no.

    If you look at the wiring diagram above, there is an input to the flasher unit from the drl. It is through a normally closed switch to ground. I assume this means that the switch opens when the drl circuit is on? What this means to the flasher appears to be the magic question. But since the switch closes to ground, it should be easy get the harness to work with my truck, assuming the connectors mate.
     
    jimilivz, Jun 4, 2012
    #3
  4. Sep 14, 2012 at 11:54 AM
    #4
    guscaralarm

    #4
    guscaralarm New Member

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    Gus
    Hello everyone, is it true that the new 2012 Tacoma sport comes on a 9v power intead of 12v?
     
    guscaralarm, Sep 14, 2012
    #4

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