Engine Coolant Temperature (ECT) Gage

The Engine Coolant Temperature Gauge is operated by two coils. Battery voltage is applied to both coils. One is grounded directly, and the other is grounded through the Engine Coolant Temperature Sensor. The Engine Coolant Temperature Sensor has 44 ohms resistance at 138°C (280°F) and its resistance increases at lower temperatures. Resistance is approximately 1365 ohms at 37°C (100°F), this causes the current through the Engine Coolant Temperature Sensor and one coil to increase as the coolant temperature decreases and moves the pointer.