The battery light come on so I went to the parts store to have them check the alternator. The idiot said it was fine and had me buy a battery. I made the trip home with everything working fine. 30 minutes later my mom went out to check it. The battery light was back on, showing 12v on the gauge while running, and the temperature gauge needle was hanging down. Today I have replaced the alternator. The battery light is off now and getting 13-14v on the gauge but the temperature gauge needle is still hanging down.

Is there a fuse or something for it? Or is it just broke? How can I check it/fix it?

 

You can check the ECT sensor output with a Tech2 or equivalent scan tool. It is possible that the gauge is bad or that the needle just worked itself loose.

 

Thanks for the reply. You know what I did? I banged on the dash and it popped right up to where it was supposed to be!
When I lost all power from the alternator, all the gauges fell to the bottom. All of them came back up with the new alternator installed, except the temperature gauge. I guess it just got stuck.

 

That's odd... Glad it is working for you now though!