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Fog Light Install w/ OEM Turn Signal Stalk / Switch

Discussion in 'Prius v Accessories and Modifications' started by Kepik, Jun 9, 2017.

  1. Kepik

    Kepik Junior Member

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    I posted in another thread about installing a turn signal stalk that had Auto and Fog selections (84140-33202). I noticed when turning the fog light on, there's a working relay for it. I can hear the relay click and the fog light indicators turns on in the instrumental panel plus it works in relation with my low-beams turning on whether it be a direct ON position or via AUTO. This makes me wonder if our v's were actually equipped (wired up) but just had missing pieces that would keep it dormant. As I scoured through the forums to find out if it was possible to do a close enough OEM install without using an external relay/harness, I found the lengthy Gen 3 discussion of the fog installation. Although, for their model, it seems as though, their relay needs to be wired up and even then, the fog light indicator doesn't like up on instrument panel (ECU issue?) Fog Lights: Install [Retrofit] fog lights on 2010 Prius? | Page 17 | PriusChat

    With all that being said, I wanted to ask if any Prius v (Lower case v, not upper case) users tried to install their fog lights in a more OEM fashion using a turn signal stalk aka Multi-Function Switch. I have a very basic understanding of circuitry and I'm thinking, if I were to power up the fog lights on an open 12V in the fuse box, would the fog light relay sense the source or would I have to tap into the relay to gain the proper switch functionality?

    Patiently waiting for the PriusChat shop to fulfill and ship my order of the fog light kit (apparently all the Southeast Toyota Dealerships got notice from Toyota to discontinue these kits, as I tried buying from them via eBay/Amazon).
     
  2. Offline

    Offline Active Member

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    You would have to power your foglights from the relay's output terminal - not a random power source. Do you understand how relays work? If you can locate the relay, you might be able to identify the output with a test light and there might even be output wires already in place.
     
  3. xliderider

    xliderider Senior Member

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    Why start a new thread? :confused:
     
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    Offline Active Member

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    If you can find the foglight relay's output terminal/wires you can "probably" snip the wires in the harness you are buying and attach the leads from the foglight units to the relay discarding the rest of the harness and the switch and relay that came with the harness.
     
  5. ChapmanF

    ChapmanF Senior Member

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    In my 2010 liftback, the relay is present and has a power source, there just isn't any wire for that pin in the wiring harness that runs through the firewall. Just a matter of running a wire through the firewall (ugh), then putting the right repair terminals on each end to fit in the unused positions of the connectors (one, the connector to the Body ECU, the other, the connector junction between the engine compartment harness and the bumper harness with the fog connectors. The wiring diagram shows clearly which pins to use at each end, and (if you click the "Wire Harness Repair" link) shows the part numbers of the repair terminals involved.

    -Chap
     
  6. Kepik

    Kepik Junior Member

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    The moderator closed it because it was too hard to follow, due to so many different topics discussed. Apparently, I was able to follow it... haha
     
    #6 Kepik, Jun 11, 2017
    Last edited: Jun 11, 2017
  7. Kepik

    Kepik Junior Member

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    Thank you!! You just made it so clear. I just realized that it's the relay that gets power which in turn, "outputs" to the fog lights. All this long, I was thinking it was Fog lights -> Power. lol I'm looking at the wiring diagrams and it all makes sense :rolleyes: The fog lights kit arrive tomorrow, so I hope to get it done by this week!

    Thank you! I'll look into that as well!
     
  8. Kepik

    Kepik Junior Member

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    Ended up getting Morimoto LED fog lights and decided to put a double layer of lamin-x on them to give it that true yellow look! The pin location in the ECU is the exact same one as the hatch, pin 8 on 2C connector. I had to buy the terminal repair kit pin 82998-24350 and shoved it in the harness plug. Got some 14 gauge wire and connected the pin and routed past the firewall. Bought a fog wire harness kit on eBay and used only the fog light connector wires.

    So there we go, I was able to use an OEM signal switch to get fog lights to work!

    20170711_010300.jpg 20170711_010313.jpg
     
    #8 Kepik, Jul 11, 2017
    Last edited: Jul 11, 2017
  9. Weirderal

    Weirderal Junior Member

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    Has anyone done a similar fog light installation recently? My friend and I have had a devil of a time trying to work out the wiring situation.

    I already installed the replacement turn signal stalk--fog relay clicks on audibly and dash indicator lights up with its use.

    But tapping into whatever power that makes available is proving impossible.
    We have a kit that's designed to be used with an aftermarket dash switch, with the intent to remove the extraneous parts of the wiring once we're sure.
    Just to test before going through the trouble of going through the firewall, we tried hooking the ground up under the hood and running the power wire into that terminal repair kit pin 82998-24350 into position 8 on 2C. But the bulb we had to test would not light up (bulb was tested separately and is good). So the power is not being delivered from there? But the power must be coming from that apparatus inside somehow since the fog light fuse is located there, correct?

    Or, assuming for manufacturing simplicity there is already some wiring to provide the power running under the hood we need to tap into, where the hell is it? 98% of the guides we can find for this involve the damn dash switch kits. It's positively ludicrous that kits for doing it this way aren't a thing, because removing the steering wheel for the turn signal stalk was pretty easy, all things considered, and looks and operates so much more cleanly.
     
  10. ChapmanF

    ChapmanF Senior Member

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    Do you hear a click from the relay inside there when you turn the stalk fog switch on and off?

    Bear in mind that will only happen when the headlights are turned on, and only for low beams.
     
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  11. Weirderal

    Weirderal Junior Member

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    Yes, with my low beams on, there is a very audible "click" ~half a second after turning the fog switch on. It's just finding where that power is being provided that's messing with us. Feels like 3 people on the internet have installed this this way rather than with the dash switches included with the kit, but I really want to make this look and feel factory-like.
     
  12. ChapmanF

    ChapmanF Senior Member

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    Well, the Instrument Panel Junction Block "inner circuit" diagram for 2010 clearly shows where the power comes out. As long as there's a fuse installed in the FR FOG slot, you can use either 2C-7 or 2C-8 (or both) to harvest the power. In my 2010 it was exactly that simple.

    2c78.png

    I suppose Toyota, at the factory, might use both output pins for more current capacity. Because I added LED fogs, I just used 2C-8, and replaced the 15 amp fuse with a 3 amp.

    Everything I've seen for the v suggested the pinouts hadn't changed, but I don't have the v diagram in front of me to look at. If there's any question, get a 2012 v diagram and see what that shows.

    Toyota Service Information and Where To Find It | PriusChat
     
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