Temperature gauge

Another fault is possible. The later models have a white engine harness connector in the engine bay. Failed connections have been found there.
Next... check that this gauge is still tight to the inst' panel circuit board. Its not unheard of for the speedy nuts that make the connection to get loose.
The thing is... A water temperature gauge has the very least duty cycle so they should live virtually forever.
In all my experience I have seen only 3 or 4 temp' gauges that were totally fried. No doubt that a serious fault such as shorted to ground for extended period caused it. Yep, chit happens. I suppose that purple wire was pinched under a slant 6 valve cover at least a hunert times. I assume that in most cases this mistake was caught and corrected before the gauge was killed.
Bottom line, be sure you need another before buying another.