Temperature gauge is not working. where is cooling sensor located and what does it look like

From what I just read about your vehicle,it has a history problem with the gauge,may be the coolant temperature sender or the gauge,it says the whole cluster will have to be changed to be fixed if the gauge is bad,found some forums and all had gauge problems.Right above the coolant temperature sensor is the coolant temperature sender,this is what sends the temperature to your gauge,the sensor sends a signal to the computer,they may have replaced the wrong one,here's a link to the sensor,the hole above it is where the sender goes,it's a one prong part,the sensor is a 2 prong part.A lot of people don't know that there are 2 types of coolant temperature gauge sending unit and sensor.

If you are refering to the Engine Coolant Temperature (ECT) sensor,it is located on the right rear of the engine below the exhaust gas recirculation (EGR) valve.

HINT: If your Deville is equipped with the analog instrument cluster and the temperature gauge is working, or if you have the digital instrument cluster and the driver information center (DIC) has been diplaying messages telling you that the engine is hot, the problem with your engine cooling fans is NOT the sensor.

your coolant temp sender could be bad. locate the temp sender. this is a 1 wire sensor. the other sensor in the block has 2 wires and starts the cooling fan.

According to Autozone.com:

Because ECT (engine coolant temperature) sensor procedures vary depending upon their location, first locate the part. You may need to partially drain the engine coolant to prevent coolant spillage.

• Disconnect the negative battery cable.
• Unplug the ECT.
• Then, unscrew it.
• Reverse the removal procedures to install the new part.
• Connect the negative battery cable to the battery.

Related Parts:



Cooling Fan Switch
Content for class "spacer" Goes Here

Engine Temperature Sensor
Content for class "spacer" Goes Here

Temperature Switch
Content for class "spacer" Goes Here

---
Coolant Temperature Sensor

Fig. Remove the coolant temperature sensor
The coolant temperature gauge sensor is a temperature-variable resistor, or thermistor. As coolant temperature increases, the resistance of the sensor decreases or decreases, depending on the type of sensor.
A1 and A2 platforms use a different type of circuit that A3 vehicles. On A1 and A2 vehicles, the circuit is a "resistance to ground" type. A3 vehicles use a "variable voltage" type, where a voltage is supplied to the sensor. Because of the circuitry design on A3 vehicles, testing of the coolant temperature gauge is limited.
The engine coolant temperature gauge uses a heat sensitive sending unit to transmit an electrical signal to the gauge. The sending unit is a heat sensitive variable resistor that is located on or near to the cylinder head and threads into an engine coolant passage. The sensors are a Negative Temperature Coefficient (NTC) type. As the temperature increases, the electrical resistance of the sensor decreases. As the coolant temperature changes, so does the resistance of the sensor. The gauge is calibrated within the operating range of the sensor and interprets the resistance value to display the coolant temperature.
Beginning with model year 1994, the engine coolant gauge and the Engine Control Module (ECM) temperature sensors were combined into one sensor with 4 terminals. The basic operation remains the same in that their resistance decreases as the coolant temperature increases, however the actual resistance values of the 2 sensor circuits are different. The electrical connector of the 4-wire terminal sensor ( 1 and 2 ) is keyed to prevent improper connection of the sensor's electrical circuit.

Fig. Beginning with model year 1994, the Engine Coolant Temperature Sensors combined the sensors for the ECM and the gauge into one sensor-1997 2.8L V6 sensor shown

Fig. The electrical connector for the combined temperature sensors is keyed to avoid improperly connecting the sensor's wiring-1997 2.8L V6 connector shown

Could be the coolant temp sensor:



4.0L engine shown





5.2L engine shown



To test it:

Perform this test on a cold or cool engine.

1. Disconnect the negative (-) battery cable.
   
2. Unplug the electrical wiring from the sending unit.
   
3. Using an ohmmeter, measure the resistance between the terminal and the sending unit's metal body
   
   1. Infinite resistance or zero resistance: the sending unit is bad, replace the sender with a new one.
      
   2. Other than infinite or zero resistance: continue test.
      
4. Remove the temperature sender from the engine.
   
5. Position the sending unit so the metal shaft (opposite end from the electrical connectors) is in a pot of water. Make sure that the electrical connector is not submerged and only the tip of the sending unit's body is in the water.
   
6. Heat the pot of water at a medium rate. While the water is warming, continue to measure the resistance of the terminal and the metal body of the sending unit:
   
   1. As the water warms up, the resistance goes down in a steady manner: the sending unit is good.
      
   2. As the water warms up, the resistance does not change or changes in erratic jumps: the sender is bad, replace it with a new one.
      
7. Install the good or new sending unit into the engine, then connect the negative battery cable.
   

1. With the engine cold, remove the ECT sensor.
   
2. Immerse the tip of the sensor in container of water.
   
3. Connect a digital ohmmeter to the two terminals of the sensor.
   
4. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the sensor resistance illustration.
   
5. Repeat the test at two other temperature points, heating or cooling the water as necessary.
   
6. If the sensor does not meet specification, it must be replaced.
   

Submerge the end of the temperature sensor in cold or hot water and check resistance



Temperature-to-resistance relationship of the ECT and MAT sensors

There will also be a temperature sending unit which provides the info to the temperature gauge. Track it down and replace it as well and you'll probably have a lot more success.

Hope this helps,
Sherwin

The Taurus has Two temp sensors. One for the dash, which is isolated, then one for the PCM, it also controls when the fan relay should actuate. Its a 2 wire sensor, just above the thermostat. If you remove the harness from that sensor, and the cooling fan comes on, at any temp, (should take 5- 10 seconds) then thats your fault.

cooling fan has a relay. check it first. Then check the ECT, Engine Coolant Temperature Sensor. It is on the engine and sends a signal to the PCM, Engine Computer.
-----------------------------------------------------------------
Section 03-03: Engine Cooling 1996 Aspire Workshop Manual
DESCRIPTION AND OPERATION Cooling Fan, Electric WARNING: WHEN WORKING IN THE ENGINE COMPARTMENT, STAY CLEAR OF THE FAN BLADE. BECAUSE IT IS ELECTRIC AND TEMPERATURE SENSITIVE, IT CAN START AT ANY TIME IF THE IGNITION IS ON.
The electric cooling fan is an electro-drive type. Its operation depends upon engine temperature and ignition switch (11572) position. If engine coolant temperature reaches 97°C (207° F) and the ignition switch is in the ON position, the engine coolant temperature sensor (ECT sensor) (12A648) sends a signal to the powertrain control module (PCM) (12A650) which turns the engine cooling fan motor (8K621) and fan blade assembly on. Because it cannot operate unless the ignition switch is ON, the engine cooling fan motor and fan blade assembly does not operate after engine shutdown. The fan control relay (FC relay) is located in the LH front corner of the engine compartment, between the battery (10655) and the headlamp assembly. Circuit protection is provided by a 30A fuse labeled COOLING FAN in the main fuse junction panel to the left of the battery. If the vehicle is equipped with air conditioning, an additional relay is installed in the circuit. The A/C clutch control relay (19D572) bypasses the engine temperature portion of the circuit. The bypass circuit allows the engine cooling fan motor to operate whenever the A/C switch is engaged.
------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------
Fuel pump/sender access is through cover under rear seat.


Fuel Gauge

1. Remove the instrument cluster. Refer to the procedure in this section.
   

1. Using a jumper, connect the battery positive terminal to the fuel gauge "+" terminal and the battery negative terminal to the fuel gauge "-" terminal.
   

1. Connect one lead of a Rotunda Instrument Gauge System Tester 014-R1063 or equivalent to the "F-U" terminal of the fuel gauge (9280), and connect the other lead to the "-" terminal of the fuel gauge.
   

1. Adjust the instrument gauge system tester to the resistances shown in the illustration.
   
   
   
   
   

1. If the fuel gauge does not operate as specified, replace the fuel gauge. If the fuel gauge is OK, return to the Pinpoint Test.
   

Fuel Level Sensor

1. Remove the fuel level sensor (9275). Refer to Section 10-01 for the removal procedure.
   
2. Measure the resistance between terminal A and terminal B of the fuel level sensor.
   
   Connector Shown From Component Side

1. Adjust the fuel tank float to the following positions:

1. If the resistances are not as specified, replace the fuel level sensor. If the fuel level sensor is OK, return to the Pinpoint Test.
   

-------------------------------------------

there is no computer to turn the fan on. it works on a thermal switch. so you have a relay to the fan. when the temp sensor gets hot it connects the circuit to the relay and then the fan is on. vary simple. and it works when the car is still hot but the key has been turned off till the switch cools off or some have a timer so it does not run for ever. so good guess is the temp sensor for the fan could be bad if the fan is working.

The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the ECM. The ECM supplies 5 volts to the coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high signal voltage which it interprets as a cold engine. As the sensor warms (internal resistance low), the ECM monitors a low signal voltage which it interprets as warm engine.
Fig. 1: View of the Engine Coolant Temperature (ECT) sensor Fig. 2: Engine Coolant Temperature (ECT) sensor locationTESTING
See Figures 3 and 4

1. Remove the ECT sensor from the vehicle.
2. Immerse the tip of the sensor in container of water.
3. Connect a digital ohmmeter to the two terminals of the sensor.
4. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the engine coolant sensor temperature vs. resistance illustration.
5. Repeat the test at two other temperature points, heating or cooling the water as necessary.
6. If the sensor does not meet specification, it must be replaced.

Fig. 3: Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensor wiring diagram Fig. 4: ECT sensor temperature vs. resistance values