On the early and late model temperature gauges there are marks that give a general sense of higher temperature and lower temperature.

Does anyone know what these are supposed to mean in terms of actual temperature (C or F) ?

Or, has anyone added a gauge that gives a reading in degrees (C or F), and if so, where was the sensor installed ?

Thanks, 

Fin Beven
'90 Carat, Camper Conversion
Pasadena, CA