What is the red light that shows and arrow pointing down into a box of wavy lines and is right below the 6 and 7 on the tach of a 93 and 94 Z28? My 93 just started with it and my brothers 94 has it now too. I checked all the fluids I can think of and can't figure out what it means.

 

That is the low coolant light. The low coolant sensors go bad often. It is located on the top passenger side of the radiator. If you unplug it, the light goes away or you can replace it like I did.