sep1234

My passenger-side low beam does not turn on either manually or automatically. The driver-side low beam turns on as it should. I have checked the one mini-relay (#47), which sends power to both driver and passenger side low beams. I also checked the individual fuses, one for each of the low beams. Relay and fuses are fine.

The "strange" issue is that both low beams will turn on, when I press the UNLOCK button on the key fob! I have duplicated this many times. Every time I press UNLOCK, both low beams turn on (as they should for about a minute or so). Every time I start the car or put the car in accessory mode while turning on the headlights manually or letting the automation control the lights, only the driver-side low beam turns on. When I flash my high beams, both high beams turn on while the driver-side low beam is on, but the passenger-side low beam will is off.

The electrical schematics for my 2005 Corvette C6 (fairly early model produced in late November 2004) show several ways for the relay to be grounded (either by BCM logic or switches). Apparently these circuits are working fine, because at least the driver-side low beam turns on. Once the relay is grounded, it sends power to both low beams. Therefore, it should not matter whether I turn on the low beams myself or the alarm system turns on the low beams after pressing UNLOCK on the key fob.

This honestly just does not make any logical sense. All I can say is that the day before I "noticed" this problem, there was heavy rain, and I did drive through some standing water.

I tried searching and reading all posts on this forum related to headlights, but I could not find a similar issue. I just happened by chance to notice that both low beams turn on, when pressing UNLOCK on the key fob. If I would not have done that, I would have concluded that the HID bulb needed to be replaced, since the relay and fuses are intact.


Jamie

Streetk14

The HID low beams come on when you press the "unlock" button on the remote? Maybe I've just never paid attention, or I have it switched off in the DIC. I thought the fog lights turned on or the running lights. Now I have to go out to my car and look. I do have a 2008, though.

If you are positive that the HID low beam comes on when you are unlocking, then the bulb is okay. I would say at your vehicle age it is a bad bulb, but what you are saying is the strange part.

Hoonose

My only suggestion is to check the wiring harness. Some early '05's, mine included had defects. I don't recall anyone having low beam troubles from this though. DRL/turn signals, yes, like mine fixed with my extended warranty.

Knob Jockey

The low beams/parking lights come on with the press of the un-lock button on the fob, at least in the dark, can't say I've noticed it in daylight. Not sure if this is part of DIC-selected 'Twilight Sentinel'.

So your confusion is well founded.

The only thing I can think of is maybe the battery is weak or the alternator is failing and when the car is running there isn't enough power to fire the passenger ballast/igniter.

There have been some posts about water getting into the headlight connector/ballast areas. Maybe check that first, and then your battery.

Good Luck, I feel your pain.

Streetk14

I checked my '08 while it was parked in the dark garage. I usually just grab the door handle to unlock the car, so I didn't take notice to the lights at all. Anyway, my car activates the halogen high beam bulbs (closest to the center of the car) when I press the "unlock" button on the remote along with the orange running lights. Not sure if earlier cars are different.

Knob Jockey

You're right, it is the high beams that come on.

I should have paid more attention. Sorry for the confusion. I'll put the bong down.

Makes a little more sense now regarding OP's issue.

Streetk14

Yeah, he just has a bad bulb

sep1234

Gentlemen,

Sorry for the delayed response. I was going to write earlier, but the wife occupied me with other things. lol....

This morning I played around with the logic of the events. As Streetk14 mentioned, the "high beams" turn on when pressing UNLOCK on the key fob. However, **** Jockey had a really good point: the electrical system (either battery, if engine not running, or alternator, if engine running) might not be able to deliver the current-draw to both low beams at the same time as other loads. So, this morning I checked that hypothesis. I pulled the drive-side fuse for the low beam hoping that the passenger-side low beam would turn on, when turning on the headlights using the lever. It did not. I pressed UNLOCK, and two lights turned on: the high beams. That is when I immediately realized that my earlier comments were incorrect. Sorry about that.... The two lights are about the same size; although, the high beams put out a lot of heat.

Tomorrow, I am going to swap the low beam modules to make sure that the bulb is the issue (most likely that is the cause). I read that there is a ballast and maybe one other part. At the price of these parts, I want to make sure that I get it right the first time. I will update this thread, when I have more info so that people in the future searching on this issue will have a diagnosis followed by a conclusion.


Thanks,
Jamie

Knob Jockey

Here's a pic of the headlight assembly laying upside down.

The silver box in the center of the pic is the Ballast for the Low Beam HID. This could be your problem if swapping lamps doesn't fix it.

The OEM HID is a D1S lamp that has the Igniter integrated with the lamp, which makes it pretty expensive.

If you replace just one side you'll see a difference in color as the HID gets bluer (color temp goes up) with age, so you might want to replace both and keep a 'spare'.

sep1234

Thanks for the pic, **** Jockey! That gives me a heads-up.

sep1234

*** UPDATE ***

This is interesting! Due to the high price of a replacement bulb for the low beam, I procrastinated about two weeks. It was on my "to-do" list to order a low beam. Yesterday evening, I was sitting in traffic on the way home from work around dusk. I noticed two spots on the truck in front of me. When I got home, I verified that BOTH of my low beams were working! I know for a fact that the passenger-side low beam was NOT working that morning, when I started my car in the garage.

Both lights were working this morning and this evening. I have turned off and on the low beams, and they both consistently turn on and off. So, here is the situation...... I drove through a good amount of water (good amount for a 'Vette) the evening before I noticed the passenger-side low beam not working. I approached the water from the left side -- passenger side of car hit water first. The passenger-side low beam was not working for exactly 14 days! If I would have replaced the bulb, it would have worked. I would have thrown out the "bad" bulb in the garbage concluding that the bulb was just "burnt out" and that driving through water the prior evening was just a "coincidence."

So, I wanted to make sure that I responded to this thread as a follow-up for other people searching on a low-beam headlight issue in the future. If you drive through water and THEN notice one or both of your headlights not working, I recommend either waiting about two weeks or perhaps removing and drying out the assembly. It is due to my reluctance to replace this part immediately, that I discovered the problem and the relationship to driiving through water. Speaking of which, the PCM also threw two error codes: MAF and downstream O2 sensor bank 1. After clearing both error codes the next day, they have not returned.


Jamie

Streetk14

That is good to hear, but keep in mind that HID/xenon bulbs can go bad intermittently. Unlike a standard halogen bulb, an HID does not have a filament that burns out. The gas charge can get low as it ages, making it harder to light off and not come on at all some times. It is actually quite common for me to see a xenon problem that comes and goes. Usually it is a bulb, or sometimes an ignitor. With the D1S-style bulbs in the C6, the bulb and ignitor are one unit.

If your problem was related to driving through the water, I'd make sure to take apart the electrical connections on the headlight and make sure the pins are all clean. If water caused the light to not work for 2 weeks, then it got into somewhere important. You don't want any corrosion to form as that could turn into a much more expensive repair down the road.


Andy

m R g S r

upgrade and go with some + bulbs such as 85122+ (those are d2s actually) you will get a few more lumens. also, as stated, replace both at the same time to have a matched color on both sides. once you replace the bulbs if you are still having problems, swap out the ballasts. you can even go with higher output ballasts such as DDM's 55watt ballasts. (they are not really 55w, actually 40 or so, but more than the stock 35watt).

sep1234

Andy,

Excellent point on the corrosion! I will remove and air-dry this light-assembly


Jamie

sep1234

I just wanted to post an update.

The low beams have been working flawlessly since October last year, when the system dried out. Now, I am mindful of driving through water, when the streets flood around here.


Jamie

redtfk

Ran into same issue thanks for help.