Re: Bosch SMS6012GB/20 timer dial not moving
No quick easy answer on this Peter I’m afraid. Water in the base almost certainly means a filling/overfilling problem has occurred. So a good clean out of the sump hose, float switch and other bits needs attention. Once that is remedied the inlet hose supply needs bleeding (i.e disconnecting then reconnecting).
The above advice may help you on this for starters but other issues may come into play on this old beast I cannot foresee based on what you have told us so far anyway.
Best of luck sorting it. They are great machines, I’ve fixed hundreds in my time so I’m well versed on them so to speak.