Engine Coolant Temperature (ECT) Gage

The Engine Coolant Temperature Gage is driven by current through CKT 135 and the Engine Coolant Temperature Sender. The sensor is a variable resistor whose resistance varies from 1365 ohms at 40°C (100°F) to 55 ohms at 125°C (260°F). As the resistance of the Engine Coolant Temperature Sensor decreases with increasing temperature, more current flows through CKT 135 causing the Engine Coolant Temperature Gage to indicate a higher temperature.

When the Ignition Switch is in the "BULB TEST" or "START" positions, current through the Ignition Switch and CKT 135 causes the Engine Coolant Temperature Gage to indicate a high temperature.