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    High beams dimmed even when turned off

    I have a strange problem after swapping outer sealed beams for H4 lamps with changeable bulbs homologated for Europe. Inner sealed beams are dimmed all the time when on low beams are turned on, see attached photo. It's similar behavior as described here. I have measured the voltage and low beams receive about 12.5V, high beams something below 2V in this state. After turning on the high beams, everything seems normal.

    I have installed new headlight switch and also new multifunction switch (the one on the steering column) but the problem persists. Is it possible that this H4 conversion somehow instantly fries one of the new parts?

    Click image for larger version

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    #2
    You have it wired incorrectly. I’ve done this myself. Someone on here has the correct pin out. I don’t remember it off the top of my head.
    ~David~

    My 1987 Crown Victoria Coupe: The Brown Blob
    My 2004 Mercedes Benz E320:The Benz

    Originally posted by ootdega
    My life is a long series of "nevermind" and "I guess not."

    Originally posted by DerekTheGreat
    But, that's just coming from me, this site's biggest pessimist. Best of luck

    Originally posted by gadget73
    my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




    Comment


      #3
      I recall my ‘87 did that until I put the external relay harness in. I don’t think the factory harness likes driving the H4 bulbs and back feeds a little into the high beam circuit.


      My Cars:
      -1964 Comet 202 (116K Miles) - Long Term Project
      -1986 Dodge D-150 Royale SE (112K Miles) - Slowly Getting Put Back Together
      -1987 Grand Marquis Colony Park LS (325K Miles) - April 2017 + September 2019 POTM Winner
      -1997 Grand Marquis LS (240K Miles) - The Daily Workhorse & March 2015 + January 2019 POTM Winner

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        #4
        During the conversion I only swapped the ground and low beam terminals in outer lamps to match H4 bulb pinout. I did not touch inner high beams connectors. I think that if the terminals were swapped the wrong way (or not at all), lights would either not go on at all or lo/hi beams function of outer lamps would be interchanged. Or am I wrong?

        The H4 bulbs that I use are 60/55W, so little bit higher wattage than original sealed beams. Maybe that's the cause why the factory harness does not like it?

        Comment


          #5
          Sounds like you did everything right, or at least the same way I did.

          I don't know if I'd trust running that much current through the factory wiring though. All the headlight power quite literally runs through the switch, which is how some folks get a melty connector and intermittent headlights.

          A basic external relay harness should fix your issue. I'm using a similar one and outside of the relays being not awesome (tossed on some Bosch ones I had), it takes the load off of the factory switch and stops the back feed issue.


          My Cars:
          -1964 Comet 202 (116K Miles) - Long Term Project
          -1986 Dodge D-150 Royale SE (112K Miles) - Slowly Getting Put Back Together
          -1987 Grand Marquis Colony Park LS (325K Miles) - April 2017 + September 2019 POTM Winner
          -1997 Grand Marquis LS (240K Miles) - The Daily Workhorse & March 2015 + January 2019 POTM Winner

          Comment


            #6
            I think thats the same kit I'm using but I found it on ebay for closer to $20. Look around, you may find it from other vendors cheaper. Works fine on the Continental and it gave me a little more than 1v improvement at the lamps. I had to rewire it for sealed beam, but no big deal. I like that my stock wiring is intact in case the relay kit fails. I can just plug the original wires in and get somewhere.
            86 Lincoln Town Car (Galactica).
            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

            91 Lincoln Mark VII LSC grandpa spec white and cranberry

            1984 Lincoln Continental TurboDiesel - rolls coal

            Originally posted by phayzer5
            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

            Comment


              #7
              Ok, thanks. I have been considering the relay mod for some time and it looks like this is the right impulse to finally do it. I ordered a H4 4-lamp relay kit that looks the same as ones you have installed and will install it as soon as it arrives. I really like the simple "plug&play" nature of it.

              Comment


                #8
                I have a strong feeling that it is not wired correctly and if you double check you'll find the issue. I had this problem too and had to repin the connectors, and the problem went away.

                Code:
                Facing the connector, 4656:
                    _
                    H
                |G    L|
                
                H4:
                    _
                    L
                |H    G|
                If you plug an H4 bulb into a connector expecting a 4656, you apply the low beam voltage to the ground terminal, and the bulb grounds through the high beam terminal (therefore, it applies voltage to the second lamp).

                Now, with the relay harness, if it is pre-wired expecting to go from 4656 to H4, you don't want to change anything. I'm not sure if that's how they are, I wire my own relays.
                Last edited by kishy; 07-17-2019, 10:59 AM.

                Current driver: Ranger
                Panthers: 83 GM 2dr | 84 TC | 85 CS
                | 88 TC | 91 GM
                Not Panthers: 85 Ranger | Ranger trailer | 91 Acclaim | 05 Focus
                Gone: 97 CV | 83 TC | 04 Focus | 86 GM
                | Junkyards

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                  #9
                  Today I went and checked the wiring again. 87gtVIC and kishy were right, high beam and ground terminals were interchanged. Swapped them out and lights work fine again. During the conversion, I must have accidentally repositioned all the terminals instead of just swapping two of them.

                  Different schemes available online confused me when doing the conversion, because the connector can be mirrored. It is often hard to comprehend if the scheme is drawn from the bulb side or from the wires side.

                  Anyway, thank you all for help. The relay harness is on its way, so at least I finally decided to do the relay mod.

                  Comment


                    #10
                    Excellent.

                    Regardless, the relay mod will be a nice addition.

                    I picked up the cheapie china one for my fathers mustang. It has been good to him.
                    ~David~

                    My 1987 Crown Victoria Coupe: The Brown Blob
                    My 2004 Mercedes Benz E320:The Benz

                    Originally posted by ootdega
                    My life is a long series of "nevermind" and "I guess not."

                    Originally posted by DerekTheGreat
                    But, that's just coming from me, this site's biggest pessimist. Best of luck

                    Originally posted by gadget73
                    my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




                    Comment

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