Couple more.
Operation
The coolant sensor is a thermistor (a resistor which changes value based on temperature) mounted on the engine coolant stream. As the temperature of the engine coolant changes, the resistance of the coolant sensor changes. Low coolant temperature produces a high resistance (100,000 ohms at -40°C/-40°F), while high temperature causes low resistance (70 ohms at 130°C/266°F).
The ECM supplies a 5 volt signal to the coolant sensor and measures the voltage that returns. By measuring the voltage change, the ECM determines the engine coolant temperature. This information is used to control fuel management, IAC, spark timing, EGR, canister purge and other engine operating conditions.
You must be registered for see images attach
this is also the proper inset for the fan. i think yours is in too far.
You must be registered for see images attach
You must be registered for see images attach
there is your sensor. the blue dots that black wire, is shared between TPS and the ECT. The shared wire should be a 5 voltreference and that is going to stay as close to 5v as the computer can do, which is pretty darn close under most conditions. that should not ever pull low or go high and shouldnt be more than .03 volts usually one way or the other minus a quick dip but recovery if like alternator gets taxed possibly. That wire should be checked for integrity and any disruptions and make sure key on its working. the other wire to the PCM would be the one which will read based on the sensors temp. The ground you identified goes to the engine somewhere. Can you show me that ground?