Out of the blue...low-beam headlights won't turn off. Discovered when I tried starting my car after work and the battery is dead. I know it's low beam becuase I have to remove the two 10A fuses in the engine fuse box for the low beam circuit to get the lights to go out. There are no headlight relay(s) for the 2007 so I assume the circuit is controlled by the BCM. I removed power to the BCM (removed the 30A and 40A BCM 1&2 fuses in engine fuse box) and the lights still remain on! I also disconnected the harness from the light switch on the steering column with no result. Only way to get the lights off is to remove the low beam fuses or disconnect battery. My next shot in the dark is to replace the engine fuse box??

Any suggetstions? I've conducted an exhaustive search of 'net and this forum with no luck.

Thanks,

Broken BALT in San Antonio

 

Are you on stock headlamps? No HID or aftermarket?

 

They are controlled by a relay that is in turn controlled by the pcm.There is one for the high beam as well but not sure if they are the same maybe you could swap them and see if the problem goes away.Thus pointing to the relay getting stuck on.

 

Yes, stock lights (no HID). Also, there are no relays for hi/lo beam on '07s and newer. And I forgot to mention that car is out of warranty so dealer will be a last resort.

 

there is no PCM, there is an ECM, TCM, and BCM, the BCM controls your lights, try removing your multifunction switch, if they still don't shut off, the BCM is most likely at fault.

 

Thanks......I disconnected the harness from the light switch and no impact. I also disconnected the BCM and lights remain on. That's why I'm assuming the fuse board in the engine compartment may be bad if the BCM was taken out of the circuit. Is this a false assumption?

 

unfortunately the electronics on these cars (even on my 07 ion2 without auto headlights) are so complicated I can only tell you what makes sense to me after doing electronics/avionics for 7 years, and to me it sounds like a BCM issue, call the dealership and ask them what they think, some dealerships will give you general guidance as long as they know what's actually wrong. As much as I hate to say it, this is most likely beyond you, me, or anyone on this site's knowledge, so you most likely will need to take it in. good luck

 

Thanks again. I called the dealer...the service advisor I spoke with has not heard of a similar problem with the Cobalts. It will cost $85 for a check out so I'll head that way.

 

Thought I would post the outcome to my problem in case a future member has to search for a similar issue.

Turned out the underhood fusebox had water damage. Service writer at dealer knew the source of the problem before the car entered the garage. He said this is a common problem where water gets past the fusebox "dust cover" and damages the internal circuit boards. He compared the action to getting your cell phone wet. Of course the repair is not under warranty and I'm left wondering how I'm going to seal this sensitive electrical component that's exposed to the elements!

 

As in your warranty has run out or they will not cover it?

Either way, if the design of the fusebox cover is that poor that water can get at electronic components I would be raising a stink.

My $0.02

 

this is not a problem with ions, are the fuse boxes different? I wonder why this would be a "common" problem with one and not a problem with another.

 

dont know y but its out of warranty

 

Doh, musta missed that Sport08........guessing must be over mileage then.

Would still be having a little quality time with the sm, should be able to get a little goodwill fix - unless something else happened that broke something on the box.

Ask and ye may receive....don't ask and you know you won't......

 

Car is out of warranty with 40K miles on odo. I requested a "goodwill warranty" arguing a design defect led to the failure. If this box is so sensitive to moisture that is should not get wet then why is it mounted in the engine bay?

 

This is probably why they ended up putting the battery in the trunk.

 

That bites.....4k over and no way? Yeeesh
Not only is it a poor design, it could have potentially fatal consequences......what if, instead of staying on, they went out....while you are booking 65mph on a dark road????
I would expect the goodwill warranty would cost GM a lot less than the lawsuit your survivors would file........


No room for the battery under the hood really, and these cars sure don't need any more weight on the front end. Maybe they shoulda put the electrical boxes back there too?

 

GM released info to all dealers to cut down on the majority of goodwills....this is part of their recent changes due to their financial status

 

Good point on the goodwill issue...but in all fairness to GM this has been a great car since I bought it new. I've actually been thinking about buying a new one...the dealers are practically giving them away and I qualify for additional savings with the GM Military Discount. I'll just have to remember to wrap the new fusebox in Saran Wrap!

 

Silicone the lid shut to solve the problem .Also inspect the seal because Im sure its suppose to be water tight.
You dont have to access it to often anyway..

 

use weather stripping, you can still remove the lid and the weatherstripping is easily replaced

 

The weather strip is a great idea. I'll buy the thin strip with adhesive on one side.

 

I'm having the same problem. I bought the car Saturday, and just yesterday it started with the headlight problem. I took it back to the dealer to get fixed. I hope they don't plan on charging me for it since I just bought the car. How has your weatherstripping solution held up?

 

It wasnt a 07 LS was it ,maybe you bought the original posters car.

 

lol, no. It's an SS/SC

 

im having the same problem now, i have to flip to high beams then low beams nad it goes out. pain in the ass tho, whatd they do?