Temp gauge stuck - 1999 Mercury Grand Marquis

It is impossible to answer your question without knowing the YEAR, MAKE, and MODEL of your vehicle.

when a temp gauge drops to cold ,it indicates a problem in the cooling system
temp gauge sender units need water to activate the resistance that makes the gauge read so a falling gauge indicates no water around the sender unit --- air lock in the system--faulty wire connection to the gauge sender unit
the ac unit is not connected to the temp gauge so there may be another separate problem there
the temp sensor is an entirely different unit to the temp gauge sender unit and the short term working would be from an altered coolant level from changing that sensor --air lock in system
the temp sensor connects to the ECM to activate the fans and monitor engine operating temp so as to keep the air/fuel mixture exact for the engine conditions
the temp sender unit just makes the temp gauge read
a faulty thermostat will either be stuck open and the engine temp will take a long time to rise or it will be stuck closed and that will cause an overheat very quickly

Take out the gauge and clean with some cleaning spirit to make sure the dial is moving. IF TOO STUCK TO BE LOOSENED BY CLEANING THEN REPLACE.

The temp gauge and battery light issues may not have been related.
The gauge reads high when the circuit to the temp sending unit is grounded. It could be the gauge on the dash, or a wiring problem, or the temp sending unit on the engine.

bad gage sorry to say

Maybe temp sensor became disconnected, or damaged.
Look for it in the engine block, right by the radiator hose intake. Test the gauge by shorting the wires that lead up to sensor. If gauge reads full temp, gauge and wiring is ok. Next clean the contacts at the sensor, and if not successful, replace the sensor.

Bad IPC.......If u can round up a tech 2 scanner, do a guage sweep and i bet u will see the temp guage will not operate correctly......a new IPC (Instrument Panel Cluster) is really the only fix. Once installed it has to be programmed. If u need any help send me a return message.

Hello tj60576: My name is Roger I will help you. If the temp gauge is stuck? Locate the temp sensor on the motor.Disconnect the wire. After disconnecting the wire. Ground the plug end of the wire. You can do this with a extra piece of wire. Observe the temp gauge with the key on. The gauge should move to cold side of the gauge. If the gauge still reads hot or above then the problem is either in the dash or the gauge itself. You will find the sensor located on the cross over pipe front of the engine far right hand side of the tube.
Should you need further help please just ask. Please rare the answer you received. This way I know the answer helped. Thank You for using Fix Ya. Roger

change the thermostat it is stuck open
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