08 prius aftermarket foglight wiring

Discussion in 'Gen 2 Prius Accessories & Modifications' started by richard203, Mar 6, 2020.

  1. richard203

    richard203 Junior Member

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    hi im planning to buy a aftermarket foglight for my prius and i have some question about wiring. my question is can i wire the foglight switch to the headlight wire so i have the option to turn the foglight off but the headlight stay on but if i dont press it the foglight will turn on when the headlight turns on?
     
  2. ydpplqbd

    ydpplqbd Member

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    #2 ydpplqbd, Mar 6, 2020
    Last edited: Mar 6, 2020
  3. ydpplqbd

    ydpplqbd Member

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    Dup posting. oops!!
     
  4. richard203

    richard203 Junior Member

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    my question is 1 wire goes to battery, where do most people tap that wire from?
     
  5. ydpplqbd

    ydpplqbd Member

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  6. richard203

    richard203 Junior Member

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    is the underhood battery postive jump point easy to tap to?
     
  7. ydpplqbd

    ydpplqbd Member

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  8. richard203

    richard203 Junior Member

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    oh i see you can take the nut off the + on the jumper location and add a wire onto it. where do most of the member buy their aftermarket foglight kit from? i see some have not so good quality and fitment.
     
  9. 69shovlhed

    69shovlhed Surly tree hugger

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    the problem with aftermarket lights is they aren't designed to fit in the factory cutouts. and there's nothing solid to attach universal brackets to. best to get oem style lights, and make sure they have the SAE number on the lens. the cheap oem style lights don't fit well either and will flop around when you go over bumps.
     
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  10. richard203

    richard203 Junior Member

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    so aftermarket foglight doesnt have sae number on the lens correct? can i get aftermarket bottom grill and aftermarket foglight cutout but get oem foglight?
     
  11. 69shovlhed

    69shovlhed Surly tree hugger

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    in theory the oem style aftermarket fogs that do have the sae number are supposedly designed to fit correctly. I bought some oem style fogs w/out the sae and they didn't fit properly and were loose in the mounts. I believe there are kits with the grill cutouts and oem style fog lights that should fit just like genuine Toyota, but I ended up buying used genuine lights to replace my cracked fogs and fitting them with led bulbs. led bulbs are another can of worms; many of them are garbage that quit working or strobe after a very short time. I still am not sure if there is any brand that can be trusted, or are not counterfeits from china.
     
  12. Noob821

    Noob821 New Member

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    Can you post a link to the complete fog light kit you end up using? Thank you
     
  13. richard203

    richard203 Junior Member

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    i might try this foglight its meet or exceed dot & sae standard. but im sourcing out a used set with the griille but ill see

     
  14. richard203

    richard203 Junior Member

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    for the foglight switch where do most people tap the ign wire to?
     
  15. ydpplqbd

    ydpplqbd Member

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    Remember you have will two ("2") 12V sources needed for the "Bosch style relay. Namely, "Contact 30" and "Contact 86". See wiring diagram that I posted above.

    Contact 30: Obtaining 12V (or thereabouts) from under hood jump point DOWNSTREAM of inline fuse (youn also need to install the inlibne fuse).

    Contact 86: Obtaining 12V (or thereabouts) from low beam hot lead. This can be sourced underhood near the driver side headlight (from the conductor providing 12V to the low beam headlamp). Or, this can likely be sourced under the dash adjacent to steering column where harness for headlights runs down from column towards the firewall. I would probably obtain 12V from low beam headlight wire (as I try to avoid crawling under dashes these days but I do if have to).

    You need to figure out how you are going to splice into the headlight low beam conductor. Crimpable solderless conductors do not hold up over the long term here in the land of snow, rain and salt. As a result, I would likely cut wire to low beam, add additional wire as relay trigger (AKA "Contact 86") using sold connection and then use heat shrinkable tubing (and electrical tape) to seal up the low-beam headlight splice connection.

    Let us know ho you make out.
     
  16. richard203

    richard203 Junior Member

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    so i brought this fog light switch from amazon.



    Foglight Switch

    black wire - to ground
    red wire - it say connect to a 12v+ accy wire so what wire should i tap this to?
    blue wire - connect to 85 relay
    yellow wire - to battery
     
  17. ydpplqbd

    ydpplqbd Member

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    gen2_foglight_revised_wiring diagram.JPG Based on question #1 and answer #1 on Amazon, I am treating this switch as a single pole single throw ("SPST") switch with a lighting circuit. I have pasted Q1 and A1 from Amazon here as follows:


    Q1 (from Amazon for this item): Is this a ground circuit switching dash switch or a hot circuit switching dash switch?

    A1 (from Amazon for this item): It is primarily intended for a hot circuit switching application. I however did use it in a ground circuit application. The black and red wires are used only to illuminate the foglight symbol. The yellow wire is a 12v supply input and the blue wire is the 12v load output. The "on" indicator lamp is lit when there is 12v on the blue output wire. You can use the switch as-is in a ground circuit application, but the indicator lamp won't function. I did this by grounding the blue wire and connecting the yellow wire to the circuit. You could also use this switch with a relay in a ground circuit application to restore the indicator lamp function. By Rick K on November 4, 2017

    See: https: // www. amazon. com/iJDMTOY-Factory-Background-Indicator-Compatible/dp/B06XC43SZ6/ref=as_sl_pc_tf_til?tag=priuschatcom-20&linkCode=w00&linkId=&creativeASIN=B06XC43SZ6&th=1
    ============================================================================

    The wiring diagram that I provided previously envisions a separate switch and a separate relay and NO lighting circuit for the switch.

    Using the above switch with lighting circuit requires a change in the wiring schematic. See attached REVISED wiring diagram.

    IOW, you will need to do the following:

    1. pull a conductor from low beam headlights 12V (which we shall call "YELLOW") from underhood to the switch area of your Gen2;

    2. pull a conductor from the switch area of your Gen2 (which we shall call "BLUE") to the 86 circuit of the relay;

    3. you need to create a good grounding spot underneath your dash and connect a conductor to it (which we shall call "BLACK1"); and

    4. you will also need to create a good grounding spot underneath your hood and connect a conductor to it (which we shall call "BLACK2");

    5. BLACK1 should be connected to the black wire from the switch;

    6. BLACK2 should be connected to the conductor from the relay's circuit 85;

    7. YELLOW will be connected to the yellow and red wires from the switch;

    8. The blue wire from the switch should be connected to the the relay's circuit 86;

    9. The relay's circuit 30 is sourced from the underhood jump point with inline fuse to protect the Gen2's electrical system;

    10. The relay's circuit 87 provides power to the driving lights; and

    11. Make sure that each driving light has a good ground at, or near, the driving light mounting point.


    Comments: a.) the instructions for the switch instruct connection of the switch's RED wire (one leg of the switch's lighting circuit) to the accessory function. This arrangement (using an accessory input) will cause the switch illumination circuit to be on all the time (even when NO lights are on - not my style). While in my revised wiring plan, I have connected the lighting circuit (which apparently consists of the switch's RED and BLACK wires) instead to the low beam lighting circuit. Thereby, giving you switch illumination only when low beam is on (off with high beams and parking lights). Alternatively, you could instead connect the switch's RED and YELLOW wires to the parking light conductor which would result in driving light illumination whenever lights are actuated and the switch being lighted (whether driving lights are on or off) only when the lighting circuit is actuated (parking lights, low beam or high beam).

    b.) Based on A1 on Amazon, the relay has been placed in the 86 branch of the relay (rather than 85 branch of the relay). According to A1, the illumination circuit will NOT work on ground leg of circuit (although it looks like it should but I don't have real world switch to test).

    c.) If the power for the 86 circuit is entirely sourced (obviously through the switch on the blue output wire) from the parking light then you would have driving lights available when: i.) parking lights are on; ii.) low beam lights are on; and iii.) when high beams are on.

    PS BOTH the switch's BLACK wire and the relay's 85 circuit should be attached to body grounds (likely, one body ground for switch under dash and a second body ground for the 85 circuit underhood).

    Hope that helps. Let us know how you make out.
     
    #17 ydpplqbd, Mar 21, 2020
    Last edited: Mar 21, 2020
  18. richard203

    richard203 Junior Member

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    alright thanks my stuff is coming mybe this week depend if theres delay. if theres any more question i'll post here and post how i hooked up.
     
  19. ydpplqbd

    ydpplqbd Member

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    You may want to do a mockup of the wiring with items mounted on a scrap of plywood with the wires connected and a 12v battery. This way mistakes will not trash your Gen2 electrical system.
     
    #19 ydpplqbd, Mar 21, 2020
    Last edited: Mar 21, 2020
  20. richard203

    richard203 Junior Member

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    ya 'll do a mockup when my stuff come and let you c if this setup work or not
     
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