temperature gauge doesn't work in my car im thinking, or am i running at 100 degrees all the time? how do i fix this? thanks for any help

Temp sensor is in the drivers side head. There should be a green wire on it. If the wire is on it, you could have a bad sender/sensor or a bad gauge.

If it's cold out & you've got a bad thermostat, it is possible for the gauge to never get off the "100°" mark (since it's not really 100° anywys.. *my opinion).