1) Lead Terminal Voltage
1. Disconnect the lead from the coolant temperature sensor after turning the main switch off.
2. Turn the main switch on and measure the voltage with a voltmeter across the lead terminal and the chassis.
If the voltage differs from the battery voltage, the wiring harness, fuse or coolant temperature gauge is faulty.
2) Sensor Continuity
1. Measure the resistance across the sensor terminal and the chassis.
2. If the measurement is not indicated, the sensor is faulty.