coolant sensor stay on?
 

check the water radiator it was full, check the AST and the over flow tank both of the are full also. why is my coolant light keep staying on , you think my coolant sensor is bad?

Probably.
Mine did the same thing until I replaced it.

Could be. Disconnect it. Take that wire that the sensor connects to and connect another wire to it. Take the other end of that wire and ground it somewhere. If the coolant light stops after you ground that wire, then the coolant sensor is bad. If the light doesn't stop, it's something else.
I had this happen to me. It turns out that my knock sensor was disconnected. The wire on the harness for that is pretty short and the connector came loose. Might wanna check that out too.

they are 3 sensor for the coolant system right? one to the fan, one to the stock gauge and one to the computer right? my fan and the gauge both work. my question is which is connected to the computer?

????? The only coolant light is the coolant level warning, it has nothing to do with the computer. The fan is controlled by the ecu based on the sensor inputs and that sensor is on the back of the filler neck (green plug). The coolant level sensor is the sensor on the front of the filler neck (or thermostat housing, as some would call it). There is a single wire coming off it with a small white connector (clipped to the housing).
There is another coolant level signal source and that runs underneath the rats nest across the block (from the passenger side to the driver side) near the front of the block.