Water Temperature Gauge
WARNING: This page is about a different car, the 2004 Nissan Murano. However, it is still accessible from the selected car via links, so may be relevant.
The water temperature gauge indicates the engine coolant temperature.
ECM provides a engine coolant temperature signal to unified meter and A/C amp. with CAN communication line. Unified meter and A/C amp. provides a water temperature signal to combination meter for water temperature gauge with communication line between unified meter and A/C amp. and combination meter.