[Shotimes] Thermostats and Temp Sensors

[Chris "Zap"]

I know this has been a recent topic of discussion.  What I need to know is,
do I need to replace both or not?  Recently the Temp gauge has been reading
up as high as the OR in NORMAL, where it usually used to be between AL all
the time with slight fluctuation.  The radiator fan is also kicking in when
it does get hotter.  Does this mean that the temp sender is properly
functioning, since the fan is also kicking in? (They use separate temp
sensors, no?)  I'm guessing the thermostat is failing, as these symptoms are
common but not always definite.  I just want to make sure I replace the
right part(s), but don't replace something that is working fine.

Thanks,
Chris