Temp Gauge Working Intermittently - Suggestions?

I have a 68 Dart. I noticed my temp gauge working intermittently a few rides ago. Now, it doesn't work at all. My fuel gauge works. I grounded the sender cap and the gauge did nothing. I checked the volts at the sender cap and it fluctuates between 0 and 5. Is that normal or does it indicate a problem?

IMG_0308.JPG