h2o gauge

[white stallion]

sorry for my ignorance but my water temp gauge has a red light and does not move from the bottom. what does the red light mean? is my sensor out if so where is it found?
thank you for your help

 

[white stallion]

ops it is a 2001 dico ex7

 

[JohnB]

sensor is tough to see. behind ac pump in the intake manifold