Engine Coolant Temperature Gauge
WARNING: This page is about a different car, the 2002 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
The water temperature gauge indicates the engine coolant temperature. The reading on the gauge is based on the resistance of the thermal transmitter.
The engine coolant temperature will vary with the outside air temperature and driving conditions. As the temperature of the coolant increases, the resistance of the thermal transmitter decreases. A variable ground is supplied to terminal No. 18 of the combination meter for the water temperature gauge. The needle on the gauge moves from "C" to "H".