I didn't notice it when I was test driving the car, but now that I've had it for a few weeks I noticed that the temp gauge apparently doesnt' work.

It always stays at cold, except for one time when it rose a tad but then it went back down.

The fluids and engine oil are all fine, and I assume is a bad sensor or connection, but how do I fix it?

I'm not sure where to start.

-Peter