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I need help from you electrical guru's...

Discussion in 'Lighting' started by dak-rt-2a-XR, Apr 6, 2011.

  1. Apr 6, 2011 at 12:40 AM
    #1
    dak-rt-2a-XR

    dak-rt-2a-XR [OP] xrunner-performance.com

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    I know it is not a Tacoma, but I am having a problem with the SRT8.

    No one apparently either knows or cares about the fog light mod. I LOVE this relay because I could leave them on with brights, and I also used them as daytime running lights.

    One guy claims this can only be done by having the dealership flash the ECU to a different country of destination (to a country that does not have specifications that fogs cannot be on with highs). That not only sounds weird, but most likely expensive if they would even do it.

    The SRT8 has two fuse module/relay boxes, one under the hood and one under the trunk. I was wondering if any of you who understand wiring diagrams and know how the Toyota fog light relay worked could give these a look-over and see if you can see a comparable way to do the same thing.

    The headlight switch looks like the attachment.

    The wiring diagrams are in this thread and includes pics and what each place does

    http://www.lxforums.com/board/showthread.php?t=19755

    If you do not know what your doing or just "taking a guess," please do not bother, I do not wish to start blowing relays during some experimental process...

    $10 reward via pay pal who successfully figures it out...would be freaking sweet to be running 55w 6K lows, highs, and fogs all at once, I could see forever in front of me lol

    Fog light switch.jpg
     
  2. Apr 6, 2011 at 12:51 AM
    #2
    Matic

    Matic Locked and Lifted "02" DC TRD.

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    Why don't you save yourself a lot of trouble and headache and just wire it to a separate fuse and switch?
     
  3. Apr 6, 2011 at 5:06 AM
    #3
    Pugga

    Pugga Pasti-Dip Free Since 1983

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    The ECU thing sounds like a hoax. I doubt the ECU controls the fog lights but there's a simple way to figure it out. Trace the wire from the back of the fog switch. I would put money on it being wired similar to our Tacomas, hard wired, fused and relayed so they can't come on with the high beams or unless the lights are on. Find that relay and swap a wire out and you're good to go.

    Or use Matic's approach and rewire it yourself using a simple relay and the stock switch. It'll cost you a couple $ in wire and a simple relay that you can find at any auto parts store.
     
  4. Apr 6, 2011 at 6:13 AM
    #4
    dak-rt-2a-XR

    dak-rt-2a-XR [OP] xrunner-performance.com

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    you guys are talking to someone who doesn't know a lot about wiring LOL

    So pull the switch, trace the fog light to its relay, pull the wire, and put it in a separate relay of its own? Looking at the diagram I thought the fogs had it owns relay already?
     
  5. Apr 6, 2011 at 6:52 AM
    #5
    Pugga

    Pugga Pasti-Dip Free Since 1983

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    The fogs do have a relay of their own which is what prevent them from being turned on unless the low beams are on. Once you locate this relay, you can change the 'switch' power to something that is on whenever the ignition is on.

    Relays work as sort of an 'if-then' switch for circuits. For example, in order for the fog lights to work, the dash switch has to be on and there has to be power running through the low beam wire. There's a wire tap coming from the low beam power circuit that trips the relay allowing the fogs to come on. When that low beam circuit dies (either you turn off your lights or switch to high beams), the relay is switched off and your fogs turn off regardless of the switch position on the dash. What you need to do is change the configuration so the relay gets constant power from a trip wire that is hot whenever the ignition is on. This allows the fog lights to be on whenever the car is 'on' and the fog light switch on the dash is on.
    This below should help:
    http://www.the12volt.com/relays/relays.asp
     
  6. Apr 6, 2011 at 7:19 AM
    #6
    dak-rt-2a-XR

    dak-rt-2a-XR [OP] xrunner-performance.com

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    Ok if I do this, would I need to put in a new switch for the fogs or would it still work from the OEM switch?
     
  7. Apr 6, 2011 at 1:20 PM
    #7
    caribe makaira

    caribe makaira Lurker No More

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    Without the wiring schematics you are "blind". Just showing relay & fuse location is not enough.
    If the fog switch at the dash goes to ground to activate the relay you have a fairly easy possibilty. The issue is , like in the Tacoma, where does the relay get its juice to activate the coil in the relay. Bypass that without throwing a code or "short" and your almost done. Get a pic of that switch from the rear...(to be continued...)
     
  8. Apr 6, 2011 at 1:29 PM
    #8
    bizjettech

    bizjettech Well-Known Member

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    Its easy to figure out what is X1 and what is X2 (power and ground) of the control circuit of a relay using a MM. Sometimes the relays are marked X1 and X2 - this is what controls the relay. Automotive circuits are fairly simple overall.
     
  9. Apr 6, 2011 at 1:36 PM
    #9
    bizjettech

    bizjettech Well-Known Member

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    Sorry guys.....just re-read my last post. I do not mean to insult anyone. There are a lot of talented people here. Lots of good info and input from all! Just dont be scared away by wiring issues, it is pretty easy once you learn the basics, it will come to you the more you experiment with it.
     
  10. Apr 6, 2011 at 2:16 PM
    #10
    caribe makaira

    caribe makaira Lurker No More

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    ...continuation...After downloading the 2005 LX manual from your link, I've concluded that you can bend pin 85 from the fog relay and mate a connector to a 16 awg to a on-off switch in the cab. You'll loose the use of OEM one. The OEM switch is connected to CAN BUS, which does many things, among them shut off the fogs if HIGH beams are selected.
    Not a nice, thight solution, but...
     
  11. Apr 6, 2011 at 8:30 PM
    #11
    dak-rt-2a-XR

    dak-rt-2a-XR [OP] xrunner-performance.com

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    Yeah that is what my research lead me to find, I'm not the only one who had thought about this. Apparently the fogs are hardwired to brights and the trigger is there. In order to rewire I'd have to take apart steering colum and trace the wires out, which is way to much work! I'm going to attemp to go to dealer and see what they say about flashing my computer to tell it the car has no fogs (which apparently would bypass the relay and make fogs work only when I activate them)

    Thanks for your help!
     
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