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How to connect JDM Headlight wiring harness to USDM Headlight wiring harness?

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Old 03-08-07 | 02:00 PM
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Default How to connect JDM Headlight wiring harness to USDM Headlight wiring harness.

got my jdm headlights but when i test the usdm wires its like it switches polarity from hi beam to low beam, and i cant figure out which one is ground. Anyone have a quick fix for this? like wire color to wire color?


EDIT: Fixed at the bottom, now a how to with pics, thanks all!

Last edited by Jurassic; 03-10-07 at 11:57 AM.
Old 03-08-07 | 03:19 PM
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the two thinner wires are what you want to use to get the low beam working. i haven't had time yet to figure out the circuit to get the fogs to work again... i'm using an HId kid, so i don't need to wire up the brights, but the fogs don't work just using the two thin wires. one is ground, one is positive, but it does't matter which you hook up to the H4 bulb, it will work either way. just make sure you are using the low beam filament, no tthe high beam.
Old 03-08-07 | 04:40 PM
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find a harness to convert ur H3 harness to the H4 plugs used in the later models and JDM headlights.
Old 03-08-07 | 10:11 PM
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Originally Posted by Jurassic
got my jdm headlights but when i test the usdm wires its like it switches polarity from hi beam to low beam, and i cant figure out which one is ground. Anyone have a quick fix for this? like wire color to wire color?
Justin, I had the same problem on my 92 as well. I did it the hard way and did not use a converter wireharness to fix(wish I had known then). Anyway,, use a volt meter on the wires with the lights turned to the on position. You will get one wire which reads 12 volts, the other 2 will read nothing at all(even with the lights on). Am assuming you already hooked up the wires already, since you got a reverse polarity,,right?? Anyways, which ever 2 wires come up with no voltage, swith only these 2 and you should be set. I had another member here (Absolute) help me with my wire install and he should still be able to tell you which one is which, so drop him a line. Am not at home now to look under my hood to tell you which color to which, sorry. Right now you have a reverse polarity which looks something like this.....

Took this right after I got my JDM headlights,, see how dim my lows are,, fogs are clear b/c I took the yellow lens out. Make sure you get wire harness which can handle the output from a H4 bulb and not a generic harness like I got; reason why my lows are so dim. I found mine at autozone for like $4 for both of them. I havent installed my new harness yet, too lazy,, I just ran the wires on reverse polarity and aimed them way down so I would not blind anyone. This pic was b4 I reversed the polarity and found the correct harness to install. Installing my new harness this weekend while weather gets a little warmer. Wire socket from Autozone is PulseFX 84790.
Attached Thumbnails How to connect JDM Headlight wiring harness to USDM Headlight wiring harness?-p9240014_edited-1.jpg  

Last edited by trukn1; 03-08-07 at 10:15 PM.
Old 03-09-07 | 06:39 AM
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Damn.... dude lets keep this up to the top, I will need to go down this route soon. Actually, maybe I will wire up the lights before I send the car for paint.
Old 03-09-07 | 11:04 AM
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Here's how I wired mine. I got the H4 wiring harness from autozone.
Old 03-10-07 | 12:35 AM
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Absolute, this was the picture I have been looking for. I have the same harness from autozone. The wires are kinda bunched together in your pic., so give us the verbal breakdown please.

Last edited by trukn1; 03-10-07 at 05:19 AM.
Old 03-10-07 | 04:33 AM
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Originally Posted by absolut
Here's how I wired mine. I got the H4 wiring harness from autozone.
do your foglights still work? what does the thick red with yellow wire connect to? ground, low beam + or high beam +?
Old 03-10-07 | 11:53 AM
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Okay so thanks to some tips and help from you guys i got it down and done.
And i also used the autozone H4 harness PulseFX 84790, like said above.

Here is the right side, fogs, high beams and low beams all work




Here is the left side, fogs, high beams and low beams all work



if you have any questions let me know, and thanks to all that helped!
Old 03-10-07 | 04:50 PM
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Cool that is exactly what i needed to see. Absolute you are always helpful and Jurassic your pic is exactly how i needed to see things. Thanks guys. Really didnt feel like playing switch the wires until they were right.
Old 03-10-07 | 06:23 PM
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NICE....... Lexotic Stepping up to the LS level now I am gonna do that mod tomorrow!
Old 01-30-10 | 10:24 PM
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Has anyone figured out how to get the fogs working with HID installed?
Old 01-30-10 | 10:27 PM
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should work the same as regular halogens.
id also have to mention mine was plug n play?

1piece lights ftw.
Old 01-30-10 | 10:55 PM
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After I installed HID with 2 wires, the fog light does not turn on

Does anyone have similar problem?
Old 03-23-10 | 11:06 PM
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Hm would the h4 specific harness fix the problem I have?

Problem: Noticed passenger side headlight was dim. Decided to change both bulbs. After install, pass side still dim. I remembered it looked like a crappy wiring job was done on that side. Previous owner must have broken the oem wire harness.

Im thinking that its not h4 specific so it does not have enough power to run the battery at full strength.

Can anyone verify if that could be right?


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