Coolant Temperature Gauge

The Coolant Temperature Gage applies voltage through CKT 35 to the Coolant Temperature Sender and Ignition Switch. The Coolant Temperature Sender is a variable resistor. At 40°C (100°F) the resistance of the Coolant Temperature Sender is approximately 1365 ohms. At 125°C (260°F) the resistance of the Coolant Temperature Sensor is approximately 55 ohms. As the resistance of the Coolant Temperature Sensor decreases, the Coolant Temperature Gage senses a smaller voltage drop across the Coolant Temperature Sensor, indicating higher coolant temperature. As the resistance of the Coolant Temperature Sensor increases, the Coolant Temperature Gage senses a larger voltage drop across the Coolant Temperature Sensor, indicating a lower coolant temperature. When the Ignition Switch is turned to "BULB TEST" or "START," CKT 35 is grounded through the Ignition Switch, causing the gage to indicate high coolant temperature.