I just got my Bose radio back from Dr Don's and reinstalled it. It works great, by the way! However, during the install, I noticed that my battery, which I had disconnected at the negative pole- has gone dead. I trickle charged it overnight, but when I drive I get the dreaded SYS flashing! I also notice that the analog guage shows charging of the battery below the middle line, although the digital show 14 plus volts. This analog guage has actually looked like this for some time. Could it be just that I need a new battery? (93 Coupe)

 

Check the voltage with the engine on at the Battery and Alternator. The voltage at the alternator should be 14.0 volts and the Battery should be 13.5-14 volts.

I would buy a new battery if the battery is questionable.

 

I disconnected and reconnected the battery and no more sys!