Water Temp Gauge screwy behavior

[elektrik]

Need some help on where to start troubleshooting my factory temp gauge. It was working fine just a few weeks ago, when I started to notice some extremely odd behavior:

- First, it occasionally jumped all the way to hot extremely quickly (Ex. from cold to hot within .5 seconds) and back down to cold. It would do this back and forth randomly with no pattern. It was as iff someone were making the gauge go short to ground and then back...

- Then, as time went on, the behavior kept getting more consistent. More cold to hot bouncing, and finally the gauge stopped working all together (it's stuck on cold even when the truck's running).

Anyone have any suggestions where to start first? I want to get this thing fixed before the HOT HOT summer in San Antonio starts (which is soon, sadly )

Thanks in advance