Ya, the sensor is probably stuck or shot.For other Nissans, The FSM says you have to replace the whole reservoir as an assembly.
Rock auto sells individual sensor/float with new gasket. Did it on my Murano.
You need access to bottom of reservoir. Check your connections/wiring first.
https://www.rockauto.com/en/moreinfo...zsO9%2BEU8Y%3D