No Low Beam Headlights
 

The low beam headlights on my 05 quit working.
The fuses for the left and right lamps are good. I replaced the relay this morning and the low beams are still not working.
Any suggestions?

Not trying to insult you with the obvious, but have you checked the position of the lamp control on the multifunction lever/stalk?

The lamp control has 4 positions. With the engine running (in Park or Neutral, of course), have someone watch the headlights while you cycle thru all the positions.

Yes.

Anyone have a solution for this mysterious low beam issue? I have the exact issue, the low beams work for a while in the morning and then cease to work. High beams and all other signals/fogs work fine.

Mine is an early 2005 and we've had a ton of rain recently and some have suggested that water may be the culprit.

Before I start swapping relays, ballasts or bulbs I wanted to see if anyone had a resolution to this problem.

Thanks!

Are you positive that during the day the daytime running lights aren't taking over? Do you have low beams at night?

Do you have 12V at the bulb?

Do you have the twighlight sentinel option and if so, turn it off, then try the headlamp switch. Trying to remember if we can even turn it off?

I am sure the low beams work.... but only for a while in the morning. Then they go out and will not turn back on until the car has sat for many hours. I have tried all combinations of leaving it on twilight sentinel, always on or twisting stalk back to turn off then forward to turn back on.

Before I start changing bulbs or ballasts I want to be sure of the issue. A friend suggested a faulty fuse but I thought a fuse either works or it doesn't and wouldn't act in a sporadic manner.

Thanks for your replies, I hope I can figure this one out. As my corvette is my daily driver I'm feeling stranded at night. :)

It is possible to have a fuse that looks good and is bad. Swap it out with a known good one. Don't cost anything.

As far as parts replacement, the three areas to check are the relay (which you've done). The multi-function switch on the column and the BCM. You can also check the harness connections and ground connections with a multi-meter and or a test lamp. Since it is both lights my guess is going to be the multi-function switch on the column.

The HID bulbs require much more than that to fire and run...12v is what he should check for at the ballast, then go from there.:thumbs:

I have power to the lights as they work for a few hours in the morning. Then they fail to work regardless of position of the switch (auto or on). I just disconnected the battery for a minute then reconnected the negative terminal.

I think it may be a bad "mini relay" in the underhood fuse block... the one in the front left part of the fuse block. It seems strange that its the only big block type relay that is stamped "siemens" whereas all the others are Delphi. Probably no biggie but what stumps me is that it works then it doesn't and I've always thought relays are either bad or good. Not intermittent.

Thanks for all the responses so far, I hope to resolve this soon.

Chris

You are correct that relays normally either work or don't work however, thats only referring to the electromagnet coil. The switch contacts that the coil provides is where the usual problem is. The contacts slowly give up over time and eventually fail. You can remove the cover of the relay or most relays and manually push on the contacts, if its only 12volts. However, I do not know if the relay in this case is running a higher voltage for the headlamp output or not being they are HIDs.

Well I found from another member that after laying an icepack on the fusebox lid for 15 minutes it worked. Yesterday the lights would not turn back on after the car was driven in the AM. Even if I let the car sit for hours.

It must be getting too hot and shorting out. I'm hoping a replacement fuse block tray will solve the issue.

My temp gun read over 150 on some of the fuses after the car sat for 5 minutes with the hood up.

http://lh6.ggpht.com/_9dBhydRVq88/TS...s144/photo.JPG

The problem with mine did turn out to be the fuse box/tray. It was replaced and no problems sense.

If its a fusebox then really, its just a bad crimp on a wire lug coming into or out of it.

Source of problem identified
 

Resurrecting an old thread.

The same thing happened to my car last week. Both low beams quit working all of a sudden, but would come back to life in the mornings after the engine had cooled down.

It didn't take long to isolate the problem to an intermittent open circuit somewhere in circuit no. 1970, the white/pink wire that goes from the BCM to pin 86 of the low-beam relay. But was it at a connector, or inside the harness, or what?

It's in the fuse box. To confirm, I removed the fuse/relay box from the car and unplugged the low-beam relay from the box. Then I hooked an ohmmeter to both ends of circuit 1970: pin F-12 of connector C3 (where the big purple-capped harness plugs in on the bottom) and the socket for pin 86 of the low-beam relay, on top.

At room temperature, the circuit had good continuity.

For fun, I placed the whole shebang inside a temperature-controlled test oven at work and set it for 80degC. Sure enough, right around 69degC the resistance took off as the circuit opened up. Then I turned on the cooler and presto, continuity returned after a few minutes.

The source of the problem is a loose connection inside the fuse box backplane itself.

I took a die grinder to the swaged ends of the four sleeves that hold the fuse box together and removed the bottom cover. Inside it's a giant punch-down block. The connector pins engage bare copper wires that are routed around a big plastic grid.

Unfortunately, it's a multi-layer arrangement, and circuit 1970 is not on the outer layer. To get to it you'd have to drill out a bunch of plastic rivets and then (it appears) disconnect the dozens of traces on the outer layer, which is completely impractical.*

So that's where I stopped, but what's happening is that a trace inside the box itself has come undone, and it opens up with thermal expansion. Your options are replacing the box, or rigging up a jumper wire to bypass the whole thing.

*UPDATE: It's not so impractical. The fusebox can be repaired. After unswaging the four sleeves, remove all the fuses and relays and the entire backplane can be removed, revealing the top layer and the broken copper wire. See here for more information.

I would think that the loss of your headlights would be a safety issue and should be reported to https://www-odi.nhtsa.dot.gov/ivoq/

I went ahead and filled out the form. Headlights going out all of a sudden is bad news. It sounds like we're all having the same problem, so I'd encourage the other posters with the same issue to fill it out as well.

I just had the same problem with my 2007 Z51 Coupe just a couple of days ago. I did fill out the online form pertaining to the safety concern.