Temp gauge not working?

I used to have one when I was doing Hvac work but those days are gone. I have a friend still in the field though that I can barrow. I had an old sensor stashed in a drawer that I put in tonight but I didn't have the chance to get the car back out.

Tomorrow I plan on spending the day working on this issue. There is nothing worse than seeing a puddle under your car after a drive.