A washer that is completely off may have no power supply or may have an internal power or control failure. A dark display does not by itself prove that the control board is faulty.
First rule out a dangerous situation
If you see water near connections, burn marks, damaged wiring, or a burning smell, do not plug the appliance back in. Isolate it from a safe point and request an inspection.
External checks
Check the power switch position and whether there is an accessible power switch provided in the installation. Verify whether there was a known outage and which other points lost service, without dismantling the outlet or inserting tools into it.
Inspect the cord and plug only from a dry position, without moving a heavy machine or pulling on the cord. If a protective device has tripped, consult the electrical trip diagnosis instead of resetting it repeatedly.
Bosch lists power and door issues among the causes of a no-start condition in its starting problems guide. In this case, a complete lack of indicators points first to power; an active panel that does not start corresponds to another diagnosis.
If the power supply is correct
The internal power supply, line filter, connections, or electronics must be checked using the applicable diagram. Do not use an extension cord, adapter, or improvised outlet to bypass a possible circuit problem.
If the outlet has not been verified or the cord shows damage, it needs electrical attention before you attribute the lack of lights to the appliance.