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Ok, I've been reading all the threads on headlight issues and I'm kind of lost and looking for suggestions.

I have a 2003 Civic EX. No fog lights.

Here is my problem.

At first I was noticing that my driver side low beam was on and off. Sometimes it worked and sometimes it did not. I replaced the bulbs on both sides. Still not working, but pretty much now it never works. The drivers side high beam works fine. I've flip flopped the bulbs and same problem.

The passenger side, both the high and low beams work fine.

Here is what I've tried so far.

-Replaced wiring harness/H4 on the drivers side
-Tried different bulbs
-Checked fuses even though I didn't think this would be problem due to high beam working fine
-I'm assuming relay is fine since there is only 1 relay for both headlights and the passenger side works fine

Then I checked for power with a simple bulb circuit tester and found 2 of the wires going to the harness on the drivers side had power when the low beams were on. On the passenger side, obviously only the 1 wire had power. I'm assuming this is the problem but I have not idea where it originates or how to fix it.

Any ideas?

Thanks

 
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might be a bad ground connection to the chassis under the bumper/fender area. you gotta remove the bumper to be able to see it. thats where the headlight harness goes. if its not getting good ground, that could be your problem.

 
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For the single bulb models the headlights are provided power at the common terminal of the bulb and the ground is provided for either the high or low beam through the headlight switch.

 
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Ok, cleaned up the ground really good, still the same thing.

Any other ideas?

 
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How does the headlight connector look ?? Has it been hot or melted ??

If you gently move the connector at the bulb does it flicker or change ??

 
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Already replaced it with a brand new one. But it looked fine.

No, no flickering when I move the connector around.

 
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Here is the schematic, It may help with troubleshooting.

I would try providing a temp ground supply to the problem low beam wire RED/WHT. If the bulb works there is a bad connection between the low beam terminal and the junction of the other sides RED/WHT connection. If you are certain the headlight connector is o.k. it would be the next thing in line and an easy test. (Don't turn on the high beams while the jumpered ground is in place !!)

VVVV There is only 1 terminal going into the switch (pin 6) and at that point it has both low beam terminals together. Seemingly it would affect both low beams.

 
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You guys think it could be the switch?

 
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Ok, I got it working with a jumpered ground. So how do I go about fixing it so I can use both the high and low beams?

 
Rep Power: 308

It sounds like the run of wiring between the low beam terminal and the junction where the other low beam connection ties in before the headlight switch has a bad connection. (they both come together to a single line before going into pin 6) Locating that junction could be a challenge.

The ideal method IMO would be run a new wire from the problem low beam connection inside the cabin and tie it into pin #6 wiring at the headlight switch.

Edit:I found another schematic but it still shows the 2 low beam terminals coming together before pin 6 of the switch but it is done inside the under dash box. If you can locate the "F" connector at the under dash box you may try moving it around to look for changes in the bulb (with your temp ground that you made un-hooked) and maybe removing and reseating the F connector. Other schematic attached.

Edit Edit: Connector F is 12 cavities and is LT GRN (light green) It is located at the left front middle of the under dash box.

 
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Ok, well, I'll be getting under the dash on Friday when I get a chance. I'll respond with how it goes.

 
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Don't know if this is a safe assumption - I only had problems with the light on one side when my Daylight Running Lights Relay was faulty. I was able to fix it myself with a soldering iron.