# One piece headlight H4H adapter for H4 LED bulbs **URL:** \ **Category:** New & Remanufactured Parts\ **Created:** [October 14, 2024, 8:49pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803 "2024-10-14T20:49:27Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [October 14, 2024, 8:49pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/1 "2024-10-14T20:49:28Z")
Purpose: H4H LED bulbs are not available. H4 may work but will require an adapter to convert the H4H headlight housing. Status: 14-Oct-2024: H4 bulbs purchased, will test-fit soon. ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [October 20, 2024, 9:01pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/2 "2024-10-20T21:01:26Z")
Bulbs have been delayed but I have the adapter printed. They are coming mid-week so I hope to test fit this coming weekend. ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [November 24, 2024, 1:22pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/3 "2024-11-24T13:22:34Z")
It took some tweaking, but it fits and LOCKS in the proper orientation. Unfortunately, it looks like the adapter is dependent on the manufacturer of the bulb because designs vary. This works with Hikari bulbs. I have not tried it running in the housing yet, and it’s made out of PLA, not ABS. ![hikari-h4-h4h-3](https://forum.g2ic.com/uploads/default/original/2X/2/20021b21c29371674761cf5d8a8b05d62197a530.jpeg) ![hikari-h4-h4h-2](https://forum.g2ic.com/uploads/default/original/2X/0/03455e673c96ec160aa24973cb75c8edfe9b540f.jpeg) ![hikari-h4-h4h-1](https://forum.g2ic.com/uploads/default/original/2X/5/5e8676b125e6eedc5297adb1a2802e1c82f0b605.jpeg) ---
**Author:** ![typer\_da](https://forum.g2ic.com/user_avatar/forum.g2ic.com/typer_da/32/13939_2.png) [@typer\_da](https://forum.g2ic.com/u/typer_da)\ **Post date:** [January 31, 2025, 5:27am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/4 "2025-01-31T05:27:40Z")
Did you try these in the housing? ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [January 31, 2025, 2:42pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/5 "2025-01-31T14:42:57Z")
No, I haven’t. I’m willing to send a few your way for just a shipping fee if you’d be a tester. Do you have Hikari bulbs already? ---
**Author:** ![typer\_da](https://forum.g2ic.com/user_avatar/forum.g2ic.com/typer_da/32/13939_2.png) [@typer\_da](https://forum.g2ic.com/u/typer_da)\ **Post date:** [February 1, 2025, 7:04am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/6 "2025-02-01T07:04:44Z")
> [@NFULFX](#): > > Hikari bulbs No, But I just found on Amazon and will order now. Have you found yellow ones or just white? ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 1, 2025, 12:39pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/7 "2025-02-01T12:39:44Z")
Yellow headlight bulbs? I wasn’t looking for them. I just used yellow in the foglight housing. ---
**Author:** ![typer\_da](https://forum.g2ic.com/user_avatar/forum.g2ic.com/typer_da/32/13939_2.png) [@typer\_da](https://forum.g2ic.com/u/typer_da)\ **Post date:** [February 1, 2025, 7:40pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/8 "2025-02-01T19:40:14Z")
Misunderstanding I was thinking middle fog lights… Ordered the bulbs, be here next week ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 1, 2025, 7:58pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/9 "2025-02-01T19:58:34Z")
Drop me an email [nfulfx@gmail.com](mailto:nfulfx@gmail.com) $5 will cover the shipping. I will mail them on Monday. Thanks for being a tester 🙂 ---
**Author:** ![typer\_da](https://forum.g2ic.com/user_avatar/forum.g2ic.com/typer_da/32/13939_2.png) [@typer\_da](https://forum.g2ic.com/u/typer_da)\ **Post date:** [February 1, 2025, 8:40pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/10 "2025-02-01T20:40:37Z")
For sure ---
**Author:** ![DaMenace](https://forum.g2ic.com/user_avatar/forum.g2ic.com/damenace/32/11471_2.png) [@DaMenace](https://forum.g2ic.com/u/DaMenace)\ **Post date:** [February 2, 2025, 5:26pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/11 "2025-02-02T17:26:06Z")
If you got another set, I’m willing to test your adapter on my Auxito H4 bulbs also. ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 2, 2025, 7:16pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/12 "2025-02-02T19:16:01Z")
Absolutely. Same instructions above. Thanks! ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 2, 2025, 9:20pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/13 "2025-02-02T21:20:21Z")
I’m printing 4 of these now for you guys using ABS material. Just for your awareness when you get them, please check to see if the bulbs lock in the correct orientation (i.e. up/down - it shouldn’t be cocked/diagonal once the bulb stops) and check clearances. The ABS material should have much more heat resistance, but please keep an eye on it. I have had no problem with the ABS battery brace in the hot engine bay, but this adapter is a lot more fragile/thin and there isn’t much room for heat dissipation. Anxious to get your feedback. ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 3, 2025, 11:36pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/14 "2025-02-03T23:36:46Z")
Dennis, Brian: They’ll be in the mail tomorrow. You’ll get an email with tracking data. ---
**Author:** ![Ashley\_s\_Owner](https://forum.g2ic.com/user_avatar/forum.g2ic.com/ashley_s_owner/32/13958_2.png) [@Ashley\_s\_Owner](https://forum.g2ic.com/u/Ashley_s_Owner)\ **Post date:** [February 4, 2025, 11:44pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/15 "2025-02-04T23:44:36Z")
I’m hoping this works! Just picked up some one piece headlights but had no bulbs. ---
**Author:** ![Camoduckb18](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/c/c89c15/32.png) [@Camoduckb18](https://forum.g2ic.com/u/Camoduckb18)\ **Post date:** [February 5, 2025, 3:46am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/16 "2025-02-05T03:46:00Z")
This sounds interesting!! I currently have jdm 1pc headlights on but still running the factory 9007 harness connector. May I please get a sample set for testing purposes too? I’ll pay for the shipping ofc! ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 5, 2025, 1:49pm UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/17 "2025-02-05T13:49:17Z")
Before I print any more, let’s get some feedback from Dennis and Brian. I believe there will be iterative changes. If you already have bulbs though, please list the make/model. ---
**Author:** ![DaMenace](https://forum.g2ic.com/user_avatar/forum.g2ic.com/damenace/32/11471_2.png) [@DaMenace](https://forum.g2ic.com/u/DaMenace)\ **Post date:** [February 8, 2025, 1:03am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/18 "2025-02-08T01:03:58Z")
I got the adapters yesterday and took off the H4 fitment rings around my LED bulbs, but noticed my bulbs had a way smaller shaft diameter. Hence, your H4H adapter rings could not lock in and the tabs on my bulbs required it to be twist in place. I tried to use the O-ring that came with my bulbs to makeup the difference but no go. I’ll try to find a way to get the bulbs centered within the H4H adapter and possibly silicone it in place to see if that will work. ---
**Author:** ![NFULFX](https://forum.g2ic.com/user_avatar/forum.g2ic.com/nfulfx/32/5_2.png) [@NFULFX](https://forum.g2ic.com/u/NFULFX)\ **Post date:** [February 8, 2025, 3:08am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/19 "2025-02-08T03:08:03Z")
Can you send me some pictures of the issue? And which brand/model of bulbs are you using? ---
**Author:** ![DaMenace](https://forum.g2ic.com/user_avatar/forum.g2ic.com/damenace/32/11471_2.png) [@DaMenace](https://forum.g2ic.com/u/DaMenace)\ **Post date:** [February 9, 2025, 1:00am UTC](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803/20 "2025-02-09T01:00:43Z")
Pics sent [Next page](https://forum.g2ic.com/t/one-piece-headlight-h4h-adapter-for-h4-led-bulbs/103803.md?page=2)