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GEN 2 Help with wiring relays for headlights

Discussion in 'Ford Raptor Lighting Forum [GEN 2]' started by dreys, Oct 28, 2020.

  1. dreys

    dreys Full Access Member

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    2020 Raptor

    I have two sets of DD lights, that are wired up to Aux 1 & Aux 2 upfitter switches.

    What I'd like to do is the following:

    When Aux 1 is on, and headlights are on - have lights on
    When Aux 1 is on, and headlights are off - have lights off
    When Aux 1 is off, and headlights are on - have lights off

    Same feature for Aux 2, the only difference I'd like to have those come-on when brights are on.

    Does anyone which wire I'd need to tap into, and how would I wire that up with two 4-pin relays (one relay per set of lights)?
     
  2. dreys

    dreys Full Access Member

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  3. smurfslayer

    smurfslayer Be vewwy, vewwy quiet. We’re hunting sasquatch77

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    I think the responsive quotes / posts are these.

    I don’t know if the pics from the above quote will come through, hopefully they do.

    1st, know that @FordTechOne has warned us on numerous occasions not to do this (headlight triggering). I have no reason to doubt his rationale and he’s documented it previously.
    2nd, I’ve done a similar operation but not equal with my b/d reverse lights circuit. In my case I wanted them on either with reverse OR with up fitter 6. Your method would be more complicated I think. I believe you could do a trigger from the headlight on condition OR up fitter switch by using 87 and 87a respectively for the triggers, and 85 going to the actual device- in your case, lights.
    Again, this is not favored by @FTO, and IMO we should probably heed his advice here. Also, I can’t take credit (or blame :p) for the reverse light diagram, I got it off another FRF member, did some internet searching to back stop it and tested it before putting it on the truck.
     
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  4. dreys

    dreys Full Access Member

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    All done!

    Now I have a set of SAE driving lights turn on when headlights are on, and set of DD Pro turn on when brights are on.

    Headlights wire triggers relay #1 that is connected to AUX1, and brights wire triggers relay #2 that is connected to AUX2
     
  5. Oldfart

    Oldfart FRF Addict

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    Please update if you have issues down the road.
     
  6. GordoJay

    GordoJay Full Access Member

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    What relays did you use? What was the activation current?
     
  7. dreys

    dreys Full Access Member

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    I've used a pair of 40 amp 4-pin relays that have been recommended for this application @ $7.36/ea
    https://www.ebay.com/itm/4-PCS-PREM...SOCKETS-WIRE-HARNESS-BOSCH-STYLE/272925506047

    On the headlight side, wire 7 is for brights, wire 8 is for low beams

    It's been about a month since I had it done, I wanted to wait a bit to see if any issues come up. Nothing, the entire setup is working perfectly with no codes or issues.

    I know @FordTechOne had an essay written on this topic, however in reality everything works just fine. It is so convenient too, I no longer need to reach to AUX every time I turn on headlights, or every time my high beams are on.

    I've also turned on "bambi" mode in the Forscan, so now when my high beams are on, all 4 lights (2 OEM, and 2 DD) are all on. Makes a world of difference on dark roads, with a single flip of factory stalk. And I can keep my eyes on the road, rather than fiddling with AUX switches.
     
  8. FordTechOne

    FordTechOne FRF Addict

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    Have you done an actual On-Demand Self Test of the BCM with ForScan while the relay is activated? There is no visual indication that DTCs have set. If you don’t find any DTCs, then the relay draw is most likely within the FET current draw threshold.
     
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  9. dreys

    dreys Full Access Member

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    @FordTechOne - I have not, but would like to do that with both relays activated.

    What are the steps in ForScan to run that test properly?
     
  10. GordoJay

    GordoJay Full Access Member

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    I found a data sheet for the MAH-112-A-4R on the manufacturer website. It looks like the same unit. Nominal coil resistance is 90 ohms, so typical energizing current would be around 130mA. That's toward the lower end of current for automotive relays. I'd love to know how much margin you have.
     

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