Temperature Sensor (Gauge): Description and Operation

Coolant Temperature Indication System
The water temperature indication system is a magnetic gauge system. It consists of a magnetic water temperature gauge mounted in the instrument cluster and a water temperature indicator sender unit.

Coolant Temperature Indicator Sender Unit
When the engine coolant temperature is low, the resistance of the water temperature indicator sender unit is high, thus restricting the flow of current through the gauge, and moving the pointer only a short distance. As the coolant temperature increases, the resistance of the water temperature indicator sender unit decreases, causing a proportionately increased flow of current through the water temperature indicator sender unit and a corresponding movement of the pointer.