Engine Coolant Temperature (ECT) Gauge

The engine coolant temperature (ECT) gauge is operated by two intersecting coils wound around a permanent magnet rotor. When voltage is applied to the coils, a magnetic field is generated. The magnetic field causes the rotor to rotate and the gauge needle to move. The magnetic fields are controlled by the engine coolant temperature (ECT) gauge sending unit. As the resistance in the sending unit varies, current through the gauge coils changes. The gauge needle moves according to the changing magnetic field.