What's wrong with my car radio?

Earlier this year, my car radio suddenly stopped working. When I first started the car, it would work for a couple of minutes and then go silent. The lights on the faceplate continued to light up, but absolutely no sound. Once it went off, I couldn’t get it to work again unless the car had been turned off for some time (at least 5 or 6 hours). It eventually (within a month) got to where it would not produce sound at all. I think I replaced my car battery about this time, but I don’t remember for sure - I could be confusing it with my mom’s car, which did get a battery this summer.

Then earlier this week, my car suddenly died and the mechanic replaced my battery and alternator. The radio worked for two days afterwards, but now has started going silent after less than a minute.

I had hoped the battery/alternator had been the problem, but it appears that is not so. What could be wrong with it?

Something very much like this happened to me when I got my car battery replaced. It turned out that, as a security feature (i.e. to prevent anyone else from getting any good from it if it were stolen) your radio may have to be re-set with a security code that only the dealer can provide you.

And good luck with that. I had a Kia that this happened to, and I went round and round for weeks with the dealer, they couldn’t get the code from the factory, they had to take the radio out to get the serial number, etc and so on endless agony without hope or benefit.

I finally gave up and bought a different radio (not from the dealer) and had it installed, just so I wouldn’t have this hassle.

The security code is usually printed on the car’s manual, a separate manual for the radio or on some card.

Newer radios are more sophisticated. They don’t require a security code but can access the car’s VIN. If the VIN is different (ie. the unit was installed on a different car) the radio won’t start.

Now the OP’s problem sounds more like a faulty unit rather than something caused by a battery change.