Systems Monitor Magic

[oceanpearl]

My systems monitor has not functioned for 2 years.
This year, after splashing the boat and turning on all the breakers, magically the monitor starts flashing All System Normal and the screaming buzzer is back.
Have searched many threads for a resolution but strangely, it resolved on it's own.
Any ideas what can cause this magic?

 

[PlayDate]

Bad ground wire. Usually.....if the whole system is offline it is either power to the board or a poor ground connection.