If the guage itself is broken it will have to be replaced, possibly part of the dash cluster. Might be easier to install an aftermarket guage in the dash and don't worry about the original guage. Aftermarket guages are better as they actually give you a temperature number instead of a "normal" area on the guage and you have to guess what it actually is.
temp gauge is stuck on hot
To fix the temp gauge check the temp sending unit first. A bad sending unit is a common problem with the temp system.
check the temp sending unite on the water intake
Get a new gage cluster panel.
You need to replace your thermostat to get your temp gauge to work. You can go to a salvage yard and get a replacement seat belt.
Temp. sensor my have stopped working. Quick and fairly easy fix.
If your fuel gauge is out of wack, go to the local parts store and orfer some fuel gauge wack. Pour it directly into the gauge until it is full of wack..........
A good mechanic.
Is it not working due to bad fuse?if so what fuse is it.i do not have the diagram.
low coolant could cause this . without some backround ?
Are you sure its the gauge? A quick easy test is to ground the wire to the block. The gauge should sweep to HOT and peg. If it doesnt then the gauge cluster has to be replaced. Not real sure if you can purchase just the temp gauge in the cluster though. I think it comes as one complete package. This would require some dash removal. Not dificult but time consuming. If you want to go the cheaper route you can always mount a separate temp gauge.
This could be caused by a defective/broken thermostat. It's a fairly easy/cheap part to fix.