It sounds like the guage is working fine. Since you have little or no heat when you say the guage isn't working it sounds like the thermostat is getting stuck open causing your coolant to be constantly cooled (it isn't closing so the engine can warm up sufficiently to provide heat). Replace your thermostat and I bet your problem will go away.
Low Coolant? Weak Temerature sensor? Weak gauge Gauge working properly and recording the thermostat opening and closing as engine temperature fluctuates
most likely the gauge
try replacing the thermostat
The temperature gauge on a car fluctuates because the car's thermostat is opening and closing. The gauge goes up when the thermostat closes and the gauge goes down when the thermostat opens.
Is vehicle actually overheating? Could be a bad temperature sending unit or gauge Check temperature with a thermometer If thermostat does not open vehicle will overheat
it will be the guage coolant sensor situated on the thermostat housing,its a common problem. ************************************************ Is that to say that the gauge is broken, or that it can be repaired by freeing it and covering it in WD40?
Thermostat is sticking.
Either the thermostat is not working properly or the temperature sensor is displaying wrong on your gauge.
You may need anew thermostat or the fan has stopped working.
i change the thermostat and the temp switch but still not working
Sounds like the thermostat is sluggish to react to temperature changes
It is possible that the temperature gauge has stopped working in a 1992 Tempo due to a blown fuse. It is also possible that the temperature gauge stopped working do to the temperature sensor in the engine having a short.