The temp gauge on my 1993 c1500 recently quit working.  The check gauge

test at start up indicates that the guage is working, but, while the
engine is running, the gauge never moves above zero.  Thermostat is
less than 2 years old and the engine warms normally, but the gauge
doesn't move.  Also nothing changed when I recently installed a new
temp sensor.  Has anyone had a similar problem?  Should I try replacing

the coolant sensor?