Need some help with headlight conversion. Hasn't been asked before, I promise! (1 Viewer)

TurboDennis

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So i found myself in a unique situation. Im finishing up with complete wiring swap on my truck (including dash and front harnesses) to European spec harnesses (long story).

The problem i have is that the euro harness has H4/9003 style plugs on the harness, and is fully set up for using those bulbs from the factory. It actually has same H4-style connectors for both bulbs in the head light, but one has 3 wires (for a dual filament bulb, i assume), and the other has only two. My truck (as all USDM trucks) has 9005 and 9006 bulbs.

So what are my options here? At this point im looking for the simplest solution. Is there an H4 bulb available that can mount in 9005/9006 housing? This would be preferable option. Or is there an adapter that will at least allow me to use the 9005/9006 bulbs and plug them into the front harness? (i dont want to hack up the harness). Or are there any other options (short of trying to find Euro spec headlights).
 

TurboDennis

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I used one similar to this when I converted to led bulbs. 2X HB4 9006 TO H11 880 Headlight Conversion Pigtail harness sockets GTI VW wires | eBay
There are a ton of adapters on eBay.
Im having trouble finding H4 male to 9006/9005 female adapters. This is the ONLY one that i found , and it has an extra set of wires coming out of the H4 plug and im not sure where those are supposed to connect to. Im thinking it's for a different application
I would use h4/9003 bulbs. I imagine ebay has generic housing adapter plates to do it.

There is no such thing, unfortunately. I imagine that any sort of adapter plate would change the depth of the bulb in the housing, messing up the beam pattern completely
 
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Im having trouble finding H4 male to 9006/9005 female adapters. This is the ONLY one that i found , and it has an extra set of wires coming out of the H4 plug and im not sure where those are supposed to connect to. Im thinking it's for a different application


There is no such thing, unfortunately. I imagine that any sort of adapter plate would change the depth of the bulb in the housing, messing up the beam pattern completely
OK bummer. I'm kind of out of ideas. Only thing I could think of is install some depo lights. They have h4/h1 bulb mounts. It's a nice upgrade anyway. Throw some projectors in them while your at it. Which is a even better upgrade.
 
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Only thing I could think of is install some depo lights. They have h4/h1 bulb mounts. It's a nice upgrade anyway. Throw some projectors in them while your at it. Which is a even better upgrade.
Yeah, this is what I'd do in this case. Then you can use standard bulbs and you get the benefit of a new clear glass lens, plus if you do a projector upgrade you get a better beam pattern and potentially a HID source.
 

TurboDennis

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OK bummer. I'm kind of out of ideas. Only thing I could think of is install some depo lights. They have h4/h1 bulb mounts. It's a nice upgrade anyway. Throw some projectors in them while your at it. Which is a even better upgrade.
Yeah, this is what I'd do in this case. Then you can use standard bulbs and you get the benefit of a new clear glass lens, plus if you do a projector upgrade you get a better beam pattern and potentially a HID source.
I was considering (and still am) this option as well, but i would prefer to use original head lights if possible. Not a fan of putting Chinese/Taiwanese parts on my truck. Also the DEPO lights have H1/H4 bulbs. My connectors are both H4 style, which is odd.

why not just depin the 9003 connector and repin into the 9005 and 9006 connectors
Because the pins on the H4 bulbs are MUCH bigger than 9005/9006 pins. There is no way the pins from H4 connectors on my harness would fit into the 9005/9006 connectors. Again, i dont want to hack up the harness.

@TurboDennis can you post some photos of the ends your dealing with?
Here. One connector is 2 wire, the other is 3 wire. Im posting picture of the fuse box, and the wiring diagram as well.

20200425_092707.jpg


20200425_092456.jpg


20200425_092404.jpg
 
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Because the pins on the H4 bulbs are MUCH bigger than 9005/9006 pins. There is no way the pins from H4 connectors on my harness would fit into the 9005/9006 connectors. Again, i dont want to hack up the harness.

didn't think of that, that would be a good reason to not be able to do a repin. it sounds like your options are 1. find the euro headlight set and install, hopefully the valance is the same 2. depo headlights that take a h4 bulb 3. splice in 9005 and 9006 connectors.

the connector with 3 wires you would just have to only wire in the low beam power and ground, connector with the 2 wires would just be power and ground. you can do a clean job of splicing in new connectors with some shrink tubing and wire loom wrap
 
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How have you got your truck wired up?
I think the USDM (9005/9006) headlamps turn the high beams on in addition to the low beam?
H4 bulbs are designed to switch between the two. The bulb will burn out really quick if both the filaments are on at the same time.
You'll have to check this first before you decide which bulb/headlamp you're going to use.

If both high and low turn on at the same time (when you switch to high) then you can just make a little adapter harness using these
9006
9005
H4 Male
If they don't, You'll have to add a relay in between to turn the low on along with the high.
You don't need the two pin connector at all from what I can see in the diagram. (If using a 9005/9006 headlamp)

Hope this helps

P.S. We only ever have H4 headlamps in my part of the world. I'm not very familiar with the USDM headlamp wiring so please correct me if I'm wrong.
 

TurboDennis

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Any update?
I have purchased a set of Euro-spec head lights. I figured it would be the most "correct" solution.

How have you got your truck wired up?
I think the USDM (9005/9006) headlamps turn the high beams on in addition to the low beam?
H4 bulbs are designed to switch between the two. The bulb will burn out really quick if both the filaments are on at the same time.
You'll have to check this first before you decide which bulb/headlamp you're going to use.

If both high and low turn on at the same time (when you switch to high) then you can just make a little adapter harness using these
9006
9005
H4 Male
If they don't, You'll have to add a relay in between to turn the low on along with the high.
You don't need the two pin connector at all from what I can see in the diagram. (If using a 9005/9006 headlamp)

Hope this helps

P.S. We only ever have H4 headlamps in my part of the world. I'm not very familiar with the USDM headlamp wiring so please correct me if I'm wrong.

The truck now has factory Euro-spec wiring. I found out that the Euro head lights actually have H4 and H1 bulbs, and there is an adapter used on the H1 bulb to attach it to an H4 style connector with 2 pins. Not sure why.

It's not clear from the wiring diagrams how it works, but i believe that on low only one filament of the H4 bulb works. On high, it switches to the other filament, and turns on the H1 bulb as well.

Whatever the setup is, i will be using it 100% how it was designed from the factory, so i shouldn't have any issues.
 
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I guess the 2-pin H4 connector was originally meant for the fogs on the JDM trucks.

Bulb part number 90981-13027

Not sure what type of bulb this is but it shares a base with H3 bulbs ( which is what I'm using now)

images (14).jpeg
 

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