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  1. #1

    Default Another Headlight questions (H4 and/or H1 bulbs)

    I am looking to put some modern lights in my 1985 lx convertible. I am going to add the relays as I know this is a big improvement. I was also looking at getting the HELLA 003177801 164x103mm H4 High/Low.

    My question is about the high-beam light... I know I can get a Hella H1 lens. My question is why not get two sets of the h4. When I wire them up, I will no connect one of the wires. Then I can use the same bulbs for all four lights, If I ever have an issue, I can take the h4 bulb out of the HighBeam and replace the h4 in a low-beam.

    Another questions: When low beams are on, just the Low lights on the outside would be on. When HighBeam, then both the HighBeam on the outside and the HighBeam on the inside would be on. Is that how it should be wired?

  2. #2
    FEP User
    Join Date
    Oct 2017
    south-central WY


    Yes, only the outer headlight is on for low beam, and both the inner and outer (but a different filament) are on for high beams. My concern would be that the H1 filament is located at the focus of the reflector, but the reflector shape, location, and the light projection, in the H4 bulb will be compromised because you can't have both filaments at the focus of the reflector.

    You could roughly test this by parking. after dark. facing a light-colored building and blocking the inner bulb on one side and the outer bulb on the other to see if there is a noticeably different area of illumination. Having four eyes to evaluate this would be better than two (pun). If you have a dark, deserted road you could check this while driving without attracting the attention of the wrong people.

    Now I'm going to be "that guy". The juice ain't worth the squeeze in this case, especially when you're mucking around with federal and/or state required and regulated safety equipment. If, God forbid, you are ever involved in a serious accident with injury to other persons or property, plaintiff's attorney's eyes will light up if you have altered or removed lights, WIPERS, non-DOT tires, etc. It may be unpopular on a forum dedicated to vehicle modification, but there is some legal precedent for your insurance company to decline liability coverage after the fact if you have modified your vehicle and not notified them. Tread carefully.

    Eta: I am not an attorney, and the above is not legal advice.
    Last edited by darkd0r; 05-29-2018 at 03:27 AM.

  3. #3


    Not looking for any Non-DOT. Just thinking about using only have of the inside H4 bulbs (to act as the H1 high beam). This would be so that I had more of the same interchangeable parts in the event of an issue, i could swap they as needed.

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