You probably want to check the cables to make sure they're tight and check for corrosion around the battery posts as well...also might try disconnecting the negative cable for a bit, that may clear a flashing SYS error. Other than that, it may just be a weak battery...one other thing, drive it a few times before you give up on the battery. I seem to remember that it may take 3 or so on/off cycles to reset the SYS message.
Wichita, eh? That's where i picked up my blue `94 last year...WydglydJim over on cf is also from Wichita, he has a blue `90...