- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
When the gauge doesn't work, you have to determine, is it the gauge on the dash or the temperature sending unit on the engine or a wiring problem. Try this: find the sending unit on the engine and pull the wire off it. With the ignition key on, touch the wire to a metal ground on the engine. Does the temp. gauge move? If it does, replace the sending unit. If it doesn't move, replace the temperature gauge on the instrument panel.
Sounds like you may have a problem with your coolant temperature sending unit or thermostat, locate your sending unit, unplug the electrical connector run a jumper wire across the 2 wires inside the connector the gauge should read hot when the jumper wires are connected and when you remove the jumper wire it should go back to cold this verifies your gauge and all related wiring are working properly, if it doesnt work as described you either have a wiring problem or a bad temp gauge, next if your heater output is suffering you more then likely have a weak thermostat staying open or partially open replace the thermostat with a new unit, however if you arent experiencing any heater trouble replace your coolant temperature sending unit because your thermostat is more then likely working properly.....
A faulty temperature sending unit. It should be located on or near the thermostat housing. If any of your gauges reads zero, the check gauges light will come on. Sometimes even if the fuel gauge gets too low, it will trigger the light. It may be the connection at the sending unit. It may have become loose so wiggle it and make sure it is securely connected to the sending unit. If the temp. gauge needle pegs at the top of the gauge, it means the sending unit has grounded out and is faulty. If it jumps, reads off or not at all it could be a faulty sender or a bad connection.
Unplug the electrical wiring from the sending unit.
Using an ohmmeter, measure the resistance between the terminal and the sending unit's metal body
Infinite resistance or zero resistance: the sending unit is bad, replace the sender with a new one.
Other than infinite or zero resistance: continue test.
Remove the temperature sender from the engine.
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.
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:
As the water warms up, the resistance goes down in a steady manner: the sending unit is good.
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.
Install the good or new sending unit into the engine, then connect the negative battery cable.
With the engine cold, remove the ECT sensor.
Immerse the tip of the sensor in container of water.
Connect a digital ohmmeter to the two terminals of the sensor.
Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the sensor resistance illustration.
Repeat the test at two other temperature points, heating or cooling the water as necessary.
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
sending units can be difficult to diagnose, since they sit somewhere between the sensors themselves and the temperature gauges (they may even be part of the sensors themselves, making diagnosis even more difficult). How do you know if the problem lies in the gauge itself, the sensors or the sending unit? You can always check the sensors themselves---one of the most common problems with temperature sensors located near the engine is a disconnection caused by vibration, which dislodges the sensor. If the sensor is dislodged, you can fix this problem and the sending unit should operate well.
You would only need to replace this if your temperature gauge is not working properly. Just because the thermostat was replaced does not mean the sensor must be too.
There were three different engines offered for that vehicle and there is a separate temp sending unit for the gauge than there is for the computer(PCM). The V6 4.0 SOHC ECT for the PCM and the sending unit for the gauge are both located side by side on top of the thermostat housing. The V6 4.0 EI engine ECT is located on the front of the engine, left of the throttle body, and the sending unit is located in the front of the engine, behind the alternator bracket. The V8 5.0 ECT is located in the front of the engine, below the middle of the ignition coils and the sending unit is in the same area, but toward the driver's side of the engine below the left ignition coil.
The guage and fan speeds work on independant sensors. If you can remove the plastic engine cover and locate the "sending unit" for the gauge disconnect it and restart the engine. The gauge should remain cold and not move. If this is the case replace the sending unit. This should be a single wire sender located in the waterjacket of the intake manifold look in the area where the upper rad hose enters the intake.