Coolant Temperature Gauge

The coolant temperature gage is also operated by two coils. Battery voltage is applied to both coils. One is grounded directly and the other is grounded through the Gages Engine Coolant Temperature (ECT) sensor. This has 55 ohms resistance at 127°C (260°F) and its resistance becomes greater at low temperatures. It is approximately 1400 ohms at 38°C (1 00°F). This causes the current through the sensor and one coil to increase at the coolant temperature increases. This moves the pointer.