Do not open sockets, follow concealed wiring or reach into wet spaces to find it. The installation needs a safe, identifiable means of control.
What the observation means
A nearby switch may supply another appliance. During a fault, continued wastewater inflow can remain a problem regardless of which indicator is lit.
A useful next step
Stop connected fixture use and seek appropriate help where safe isolation is unclear. Tell the service team about the access issue. Do not unplug random equipment or alter wiring as a way to determine which circuit operates the pump.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.