DTC Readout Socket 7, code 13 engine coolant temperature sensor open circuit

[dmorgan]

My code reader on the 1994 Mercedes E320 wagon 16 pin data link connector, socket 7, DTC readout code 13 shows a engine coolant temperature sensor, open circuit. Does that mean to replace the coolant temperature sensor with a new one or is something else to resolve this issue? What is exactly mean by open circuit?

On the thermostat housing on the left side of the power steering pump shows three different sensors. One has blue color on the base of the sensor, another has green color and the third one just black all around. Which one is the engine coolant temperature sensor or is it located somewhere else on the engine? I have tried to find a diagram with words to pinpoint exactly where is it at and no luck so far. Can anyone help me with this issue? Thanks for reading.