Radio works on and off

[s420]

95 S420

Problem started about two years ago.
Radio including entire sound system is just dead, you can't turn it on with the ON/volume button or any other button. Little red light is not flashing when you enter the car (I think it is supposed to flash in order to show that the anti-theft mechanism is active). So for a while I just had no radio/sound system.

Once when I had a dead battery, the little red light came on after I got a jump start. Then I was able to get the radio to say "enter code" or something like that, and when I entered the code it worked fine.

Then after a few weeks or maybe less, the radio went dead again for no apparent reason. It occurred to me that maybe it has something to do with the battery, so I disconnected one terminal of the battery, the one that is connected to the chassis. I reconnected it after a couple of minutes, then the red light came on, etc., and it was OK again.

But now this happens over and over again, usually when I haven't used the car for a few days.. Usually it can be fixed by doing the battery trick, but most recently it does not work.

I got a brand new battery a few months ago and it appears to make no difference, for better or worse.


Thanks