H4 Relay Headlight Upgrade Diagram

Discussion in '40- & 55-Series Tech' started by Rice, Jun 18, 2005.

  1. Rice

    Rice

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    Hi all. A couple weeks ago we had a thread regarding Hella/IPF light upgrades which prompted me to order some parts.

    A classic Bronco forum had this wiring diagram online for doing a relay system and I thought I'd post it here for folks in search of one.

    Note: The relays I'm using are NAPA Part # AR274. I picked this relay because it has two #87 posts (i.e. the load going to each headlight). Not that you couldn't just split the silly wire but there you have it.
    H4 Realy Wiring.JPG
     
  2. PabloCruise

    PabloCruise SILVER Star

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    Nice!

    Thanks Rice- very useful...
     
  3. haystax

    haystax

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    What setup did you go with then Rice - IPF lens with Hella bulb

    I went with the Hella Euro lens and 80/100 Xenon blulbs - lots of freakin light!

    Gonna put some tractor sealed beam 4" to use as low beams now in case of oncoming traffic, I've been informed that the new headlights are slightly offensive :D
     
  4. Rice

    Rice

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    Yes, IPF lens and Hella Bulbs. The bulbs I used were 100/55 so on low beam they give legal and non-blinding light. The high beams are truly impressive but I have to say just having strong low beams with a nice pattern was worth the expense.
     
  5. bj42turbo

    bj42turbo

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    I did this wiring and relay upgrade a few years back, it makes a huge differance

    Cheers BJ
     
  6. paranoid56

    paranoid56

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  7. Yotahilux

    Yotahilux

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    Thanks for the heads up!
     
  8. DomSmith

    DomSmith SILVER Star

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    OK so the idiot is bringing a 3 year old thread back! I have the wiring diagram above (obviously) I have everything figured out (I think) except one thing...

    The third wire connecting to the headlight (WB in my case) what do I do with that?

    I understand what's going into the relay and coming out except this...

    Ground?

    :bang:

    Pardon my stupidity...
     
  9. nuclearlemon

    nuclearlemon not an addict Moderator

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    yep. whenever you see the little arrow pointing down, that's ground.
     
  10. DomSmith

    DomSmith SILVER Star

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    OK, so "WB" is ground. My plan is to leave that wire connected and ground each relay (85) as well. I guess my big question now is...

    Do you run the relays off one side (say the passenger side) with RG (Low) and RY (High) each to a relay and just cut the other side (driver side) and cap them?

    I don't want to have to post the most hideous wiring diagram ever.... :rolleyes:
     
  11. Coolerman

    Coolerman SILVER Star

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    Yes you can do it that way. You just need one low/high signal to the relay trigger.

    You doing a before and after comparison?
     
  12. DomSmith

    DomSmith SILVER Star

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    Thanks Coolerman. Not really planning a comparison. I just know I blew a headlight fuse on my way to SnT last year and it was a PITA. Scrambling for the flashlight, cops stopped us, blah blah blah...

    Fuse block was hot as hell. I've been wanting to do this ever since. I suppose I could get a quick volts reading before...

    EDIT: What would be the other option to cutting off the opposite side? Could I just tap-in on that side too and leave them rather than capping them off?
     
  13. Coolerman

    Coolerman SILVER Star

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    Yes you can tap into them, just make sure to use quality taps. 3M taps with the gel are the best, or you can solder the taps in.

    Either method leaves the wire ends unmolested in case you sell it, and the next owner wants a complete OEM harness.
     
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