Water Temperature Gauge
WARNING: This page is about a different car, the 2004 Nissan Maxima. 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 water temperature signal to unified meter and A/C amp. via CAN communication lines. Unified meter and A/C amp. provides a water temperature signal to combination meter for water temperature gauge via communication line between unified meter and A/C amp. and combination meter.