Engine Coolant Temperature Gauge

The engine coolant temperature gage 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 sender. The engine coolant temperature sender has 44 ohms resistance at 125°C (260°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 sender and one coil to increase as the coolant temperature decreases and moves the pointer.