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Headlight Upgrade Woes

Discussion in 'Electrical & Audio' started by 86suburban, Sep 14, 2019.

  1. 86suburban

    86suburban Junior Member

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    Hey guys, I've been fighting with my headlights off and on the past couple of months while working on other things so I'm gonna break down and ask for some advice. The previous owner had already changed the light housings to the style that can accept h4 bulbs instead of the sealed beams, but didn't complete the conversion. I've tried the LMC wiring harness, and it worked but the high beams kept getting back-fed, even after switching the terminals per a post i read here.

    So I tried another h4 harness from ebay, on this one, the high beams would work, but all lights would go off on low beam setting. I got tired of fighting with it, thinking it was these cheap wiring harnesses I had, so I broke down and bought one of the Painless wiring quad h4 harnesses and installed it today. When I finished installing it, the low beams would work fine, but all lights went off when switching to high beams. While messing around checking voltages in the column around the highbeam/low beam switch, the high beams came on, and now all lights go off on the low beam setting, but the high beam works, like my cheap ebay h4 harness was doing.

    I've got 4 philips h4 bulbs installed. Should I be using different bulbs for the high beams? Maybe h7 instead of h4?

    I really know nothing about wiring and headlights if you can't tell :)
     
    Last edited: Sep 14, 2019
    C15TA likes this.
  2. 75Monza

    75Monza Full Access Member

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    Are these halogen or LED?
     
  3. Craig 85

    Craig 85 Full Access Member

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    I'll be interested in your outcome. I had a similar issue with my truck when I install the aftermarket harness with my Hella lights. High beams worked, but shut everything off with the low beams. I removed the harness and for now my Hi/low beams work with the factory harness in the upper bulbs. I haven't hooked up the bottom highbeams. This winter I was going to dig into that aftermarket harness I bought and make sure it's wired correctly for H1/H4 bulbs.
     
  4. 86suburban

    86suburban Junior Member

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    They're halogens, Philips X-treme vision I believe.
     
  5. 75Monza

    75Monza Full Access Member

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    I've honestly never bought a harness, like to make my own. I put everything on fuses and relays, similar to this.
    lgtrly.gif

    Think you do have to swap the ground and high(?) wire, can either pop it out of the plug or get something like this.
    41flfwdjvwL.jpg
    Anther thing, is this on a 4 bulb system like in your avitar? If so, then it's something like this.

    relaycircuit.gif
     
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  6. 86suburban

    86suburban Junior Member

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    It would be a disaster if I tried to make my own harness lol. Thanks for all the info, yeah it's a 4 bulb system on the one in my avatar. I'll try switching the ground. Should I be using a different bulb besides h4 in the high beams? I had these laying around so I put them in but then was thinking I don't really need the dual filaments since the highs are off when the lows are on?
     
  7. Craig 85

    Craig 85 Full Access Member

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    My Hella lo/hi beam is an H4 (top light). The hi-beam only (lower light) is an H1. Don't know if your Phillips lights are the same way.
     
  8. 86suburban

    86suburban Junior Member

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    Thanks, it'll probably be next Saturday before I can dig into it again but I'll let you know how it turns out if I get it going!
     
  9. Lefthand6

    Lefthand6 Junior Member

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    I had the same problem. Switch your high beams with your low beams. The harness (for whatever reason) needs to be switched. I guess since these harnesses are made for multi applications, our trucks are the opposite. I ended up rebuilding my harness, just to find out I needed to swap the high low.
     
  10. MikeB

    MikeB Full Access Member

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    I'm confused Headlamps that use H4 bulbs will fit in place of standard halogen bulbs, and the 3-pin connectors are the same. And unless you go with higher wattage than stock (55/60), you don't need to use relays.

    Over the years I have used Cibie and Hella headlamps with H4 bulbs in place of 7" round and 4" x 6" rectangular OE type headlamps, with zero wiring or connector mods.
     
  11. Dysco

    Dysco Full Access Member

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    Wow. Pain in the butt. Most LED headlights simply plug in the original wiring and done. H4 sounds like a hassle.
     
  12. gmachinz

    gmachinz Harnessworx Inc

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    H4s are not an issue. I think most of the typical harness places use a generic diagram for their 3-wire headlights and don’t take into account the divorced high beams in these trucks..similar to most 80s GM vehicles like Montes, Regals, Cutlass, etc they have the same problem with crap aftermarket harnesses.
     
  13. 86suburban

    86suburban Junior Member

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    Just wanted to let ya'll know I got them going in case it helps anyone else. I ended up swapping the LOW and the GROUND connections and they work great now. The harness I used is Painless Performance 30814 if anyone was interested. It's not cheap compared to the ebay and LMC one, but it is much better quality, it weighs like 10 times more than the cheap ones did lol.
     
  14. gmachinz

    gmachinz Harnessworx Inc

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    Nice! Those same 2 leads also get swapped if converting to H4/H3 style bulbs as well.
     

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