Nitro please help.

[Budga]

Am I understanding this correctly?

The ECT sensor has two wires. The ECU sends 5 volts down one wire to the sensor, then if its cold, that 5 volts passes through the sensor without resistance to the other wire and back to the ECU. But if the water temp gets above the limit, the sensor resists the 5 volts and the ECU reads low voltage coming from the ECT and sends the gauge into alarm. Is this right?

[NitroShark]

Not quite,

The ECT sensor is nothing more than a variable resistor. Its resistance varies with temperature. At 68F it should read 2.3-2.6 with an ohm meter. One side of the sensor is feed 5V from the ECU and the other goes to ground. The ECU uses this information for engine fuel and ignition calibrations and also for engine protection from overheating.

Shawn