Since they all stopped at the same time it must be something in common. Have you checked breaker/fuse? You may have a broken wire that is a common positive or negative supply. Time to break out the voltmeter, I would start by verifying power at the switches.
Another question, do they work if you lift the float switches?
Was any work done since they last worked?
1997 2400 SCR
5.7 Vortec / Bravo 2