2010 Chevy Cobalt electrical issues?

Question

I have a 2010 Chevy Cobalt that I am suspicious is having electrical issues. Here is the order of things I noticed happening

1. The turn signals stopped auto canceling, meaning that after making a turn I have to physically put the signal back, it doesn't auto stop.
2. A few weeks later the turn signals stopped making a sound when the are on. This includes turn signals and four-way flashers as well. The lights are all working, just no sound.
3. About a week after I noticed that, I noticed that my front speakers are not playing any sound. Regardless of radio/cd/aux only the back speakers are playing any sound. (Edit: This is also not the balance/fade. When that is the whole way to rear, just the rear speakers play, in the middle, just the rear speakers are playing and when I turn it to front, nothing plays anywhere.)

What should I be looking at to get to the bottom of these issues?

Answer 1

On our '07 Cobalt,

(1) I have the same non-canceling turn signal problem. I believe it's a mechanical issue. This guy says he has a fix, and an explanation. (Long, lots of pix, I'm not going to quote it ... so, -1 for me.)
(Additional info: Something I read (the owner's manual?) suggested Chevy had tricked up the switch, so it won't cancel on lane changes, but will on full turns. And ours sometimes does work - maybe when I make a more square corner. Not saying it's working right - just, they apparently made it more complicated.)

(2) The clicker sound comes from the driver's door speaker. The turn signal switch feeds the 'body control module' (BCM), which (a) drives the turn signals themselves and the dash arrows, and (b) tells the radio to click the speaker. When I looked into it for ours (same problem), I found a mix of reports: some say speaker, some radio. Your (3) might suggest the radio.

(3) Just be sure you haven't got the balance mis-adjusted or something. And I'd make sure it's not a speaker problem before pulling the radio.

There are some threads about this stuff on chevycobaltforum and yourcobalt.com

Answer 2

It is possible the BCM "Body Control Module" is failing. The BCM is totally responsible for controlling turn signals and hazard lamps, down to the flash rate (as well as every other single thing on the vehicle, except the drivetrain! Even the instrument cluster gauges and odometer mileage is mastered by the BCM.)

The other likely possibility is the mechanical "cancel" button in the turn signal switch itself (as George answered).

If it turns out to be a BCM issue, this will have to be diagnosed at a dealer. Even if you could determine the BCM is bad, the replacement will have to be programmed with a special [expensive] tool that most independent shops cannot afford and do not have easy access to. The programming loads all the specific parameters for your exact VIN of vehicle, and in some cases even provides the security to authorize use the radio. It's possible this programming has been wiped, and it thinks your radio is a basic two speaker model?

The latter is pure speculation, as the problems may not be related. I am, however, confident the turn signal loss of auto-cancel is either the switch itself, or a BCM issue. The BCM not an uncommon failure for GM vehicles from this time period. Expensive, miserable, and without excuse ... but even more unfortunately: not all that rare.

Happy Holidays; I wish for you it was a wire or a bulb ... but it ain't.

On edit:

George's answer is the correct one. If you have to physically move the lever out of the turn position, the mechanical part of the cancel is not working. Check the first site; it's a very good write-up on how to do this procedure yourself, if you're handy and/or brave. The good news is it will be cheaper than a BCM, and the part can be had off eBay or elsewhere for less than 20 bucks!