Techvegas

Hi folks, new to this forum, but it appeared to be the best community for technical questions. I have a 2003 Accord Coupe 6MT.

While on a recent trip, I lost drivers side low beam headlight. Replaced the bulb, but still nothing. Fuses are good. Tested voltage at the fuses: 14.2V on working passenger headlight (engine running), but no power on dead light. High beams work fine and all other signals, etc, work fine. In case it matters, I did get some mV fluctuations from the fuse connectors when I had someone turn the switch on and off, but only up to about 50 mV.

After grommeling around the internet, I'm thinking:

Bad relay? (where the heck is it located?)
Bad ground?
Bad multi-switch stalk?

I hate taking my car to the dealer. Not so much the money, but I take a great deal of pride in repairing things myself. Not to mention that my car has actually come back from dealer work before with "technician blight."

Help greatly appreciated.

joshcolorado

it wouldn't be the switch because the other headlight is working. I will check out my service manual when I get home later for the location of the relays and grounds, but if you're not getting power at the headlight and the fuses are fine, it's most likely the relay or ground. Did you inspect the wires at the headlight? I know their a pain to get to, at least in the i4 they are

Techvegas

Thanks Josh. I wouldn't say I "inspected" the wires, as the way I replaced the bulb was to remove the battery, which was easier than removing the interior fender splash guard. Basically could just get my hand in there to remove the connector and bulb, but not much looking-around space. Since there's no power at the fuse, and each headlight appears to have it's own ground, I want to explore that more. Any detail on how to get to the groundwire (driver side)? If it's hard to reach, is there a way to "jump" a groundwire somewhere more accessible before taking things apart?

blackaneseman

relay 39794-SDA-A03 is located in the cabin fusebox. Ive seen these get replaced on accords for the same issue your experiencing.

Techvegas

I'm going nuts looking for the headlight relays. I've pulled every relay from the underhood fuse box with no impact to the one working headlight. None of the cabin relays appear to be marked for headlights.



I found two clusters of groundwires bolted to the frame inside the driver fenderwell (pic). One was crusted in grunge, so I thought I'd found the problem. After cleaning, still no headlight.



When I have someone operate the headlight switch, I hear clicking from the underhood fusebox, but I don't think it's coming from any of the visible relays. Are there any components under the "box" to the right of the fuses in the photo?



I've attached pics of the cabin fusebox near the driver's left kick panel and the underhood fusebox. Anyone know where to find these buggers?

blackaneseman

the black relays, one of them is the headlight relay. try switching around the positions to determin which one is for headlights. all the relays are the same.

Techvegas

I wish that was the case, Blackanese, but I rotated all of the black ones with no change. Others have told me that the headlight relay is integrated into the underhood box and the whole unit must be replaced.

On another thought, if the bulb or ground was bad, would that mean I'd get zero volts at the fuse because the circuit was incomplete? The bulb is brand new and even the old bulb has an intact filiment, but I want to look at all options before replacing the fuse box. Ideas appreciated.

Ghostlab

I'm having same problem. What was the fix?

Cfusinetti

I have a 2011 ceosstour with same issue, what is the fix? Shop already charged 100+ with no fix! Leaving on a road trip in 7 days and need it taken care of.
fuses good, new bulbs, hi works, one low works.....ugh

DCFIVER

Your vehicles bulbs are powered by the drivers side and passengers side multiplex control units, respectively.

Ive replaced 100s of these units for the issue you are describing. I suggest you find a more competent repair facility,as the circuitry involved is rather simple and should be easily diagnosed.