Eurocopter: Message S/N Lights

Just out of curiosity: When I select the Eurocopter ready to taxi, the message "S/N Lights" is displayed in green on the CAD. Following the startup procedure from cold and dark I can't find the switch that results in this message. On the collective, I found the switch for the nose/landing light, but that doesn't make the message appear.

Does anyone know what this message is about?

I was sure I tried all the switches, but obviously, I didn't. Thanks!