A few weeks ago, the radio in my 2007 Pontiac g6 wouldn’t work. I tried AM, FM, and the CD and had no audio. I turned the radio off, then on and the sound began working again. A couple of days later, when I was idling in park in a parking lot, the windows began moving up and down by themselves. This week, the check engine light came on so my husband began to investigate. He noticed the temperature gauge wasn’t moving up. I said now that you mention it, it never has. I only look to see if the gauge gets too high to watch for overheating, but I never thought that it was an issue that the needle was always on the bottom. Also, when I turn the car off, it sounds like it’s still running for minutes after. This has been happening for months. He explained this was because the fan is still running. Can all these issues be related?
A lot of cooling fans will run if necessary even after the car is off, so that is probably normal.
The check engine light has a diagnostic trouble code (DTC) associated with it. Many auto parts chain stores will read those codes for free. If you give that a shot you need to write down the exact code, such as P1234 - not what someone says about it.
For the windows & radio & stuff it might be worth getting the car onto a scanner that can read what is going on in the “body control module” (BCM) or whatever its equivalent might be in this car. Some shops can do this, and some can’t so you’ll have to call around.