Temperature Gauge: Description and Operation

Instrument Cluster:

Engine coolant temperature gauge
Engine coolant temperature gauge in instrument cluster indicates temperature of engine coolant with ignition switch in "ON" position. A sending unit in engine changes resistance with temperature.


Circuit Operation

Engine Coolant Temperature Gauge
The coolant temperature gauge pointer is moved by the magnetic field of two coils at right angles to each other. Battery voltage is applied to the "C" coil from the "METER (10 A)" fuse. The circuit then divides into two. One path continues through the H coil and then to ground.

The other path goes through the variable resistance of engine coolant temperature sensor and then to ground. When the coolant temperature is high, the resistance of the engine coolant temperature sensor is low and less current flows through the "H" coil pushing the pointer toward "H" indicator. When the coolant temperature is low, the resistance of the engine coolant temperature sensor is high and more current flows through the "H" coil pushing the pointer toward "C" indicator.