Coolant Level Sensor

Some models are equipped with a coolant level sensor. Coolant level sensor is located in the right side tank of the radiator. It is a dual-probe, solid state module with switching transistor. A 5-volt reference for sensor is supplied and monitored by the ECM. If coolant level is normal, coolant is contacting both internal coolant probes. This causes the switching transistor to ground the monitored circuit, pulling the 5-volt reference low. If coolant level drops, switching transistor will open the reference circuit and ECM will see a high voltage signal, indicating low coolant and causing the ECM to turn on the low coolant light.