Chevy Cobalt 2009 Radio, watch and stereo system stopped working. I also don't hear the tick tick sound of turn signals although I can see the light for them in dashboard.

Have your battery load tested. A weak battery can make the electrical system do weird things. While you're at it scan it for trouble codes, something may turn up there as well.

Munron, thanks for the answer. However, somehow, it started working again automatically. What could be the reason?

Thanks for the answer. However, I went to an auto shop, they checked the battery and said that the battery was okay. I bought this car from someone and I am not sure, how old this battery is.

You've done the right thing by eliminating that as a trouble source. Did you have it scanned for trouble codes? That would be the next step.

Your speakers are shorted out. They are unprotected in the door and are prone to water damage.

It's been a year so I'm guessing the problem is fixed. The speakers are shielded and positioned so they don't get wet, unless someone has been in there changing things or the car has been flooded. Which, of course, yours, or Khan's might have been.

Well, somehow, it started working normally again but there were so many problems with that car. I sold it soon after buying it.

Thanks for the update.