Low Coolant Light

pull the sensor out of the overflow bottle and at the bottom of the sensor their is 2 metal tabs at the bottom of the sensor clean them with a metal brush that should fix your problem the metal tabs corrode over time which will cause them to work improperly...post results..
 
All of the above....Junk sensors known for going bad. Actually having low coolant in the overflow. Clean the prongs on it. Unhook the sensor but remember to check coolant level routinely, as well as if you get rid of the car let the next owner know.
 
i'D RATHER just replace whatever you guys are talking about.

What is the thing called I need to replace so i can tell my dad to get it at the store hes a manager at for me. its an auto part store.

Bill, I already tried cleaning the prongs, Did'nt do anything. they were dirty and such but didnt change wen i cleaned them.