Where is the coolant level sensor on 1994 Firebird?
If you have an LT1 its on the rear of the rad about 6 inches below the filler cap. its square and has a 2 wire connector pluged into the bottom of it. Your local auto parts store carries it for about 60 bucks, easier fix is just unplug the wires from it and the "low coolant" light on the dash will go out
There are two separate sensors that play here. the "coolant temperature sensor" and "coolant LEVEL sensor". I suggest confirming which of these was replaced, as it is very common for them to be confused. likely you will find the coolant sensor that was replaced was the one on the engine (temperature); The LEVEL sensor is mounted either in the coolant resivoir or in the radiator. Probably just need the proper sensor replaced.