low coolant light - help?

My 99 SE 3.1 liter low coolant light came on so I decided to do a flush. I backed-flushed the entire system and then filled the radiator and overfill tank back up to their proper levels. Now, my light stays on. Do you think it's a bad sensor? Radiator is filled right up to the top. I've put a couple hundred miles on it so it has circulated and light is still on all the time. Where is this sensor located? Thanks for the help.

Do a search here for low coolant light. The sensors go bad and can be fixed. There are lots of threads here about it.