The temperature guage will still operate on the IP cluster if the
sensor is bad.

You're headed in the right direction, though. The ECTS (engine
coolant temperature sensor). The original part was made of resin, which
cracked due to the high temperature of the coolant passing over it. The
new, redesigned OE part is made of brass for durability and to correct
this issue. If you replace it (I would, if you never have... $10 in
parts) be sure the contacts on the connector are clean.

Hopefully this won't be a double-post. The first time I tried, it
didn't show? New to this group. :-)