99 Taurus SE Coolant Light on after Antifreeze change

I just changed the antifreeze in my Taurus by seperating a coolant hose. After the refill the Low Coolant light comes on at engine start or shortly after. I've checked the fluid level in the resevoir, and the engine temp is normal in all conditions. Does the Low Coolant light take it's reading off the resevoir only? Could it be that the Coolant level indicator connection under the tank got moisture in it and is causing the misindication?

On my 97 (and 99% sure on your 99), there is only the sensor on the reservoir. It could be a fluke that this happened at the same time. The sensor is actually just a magnetic switch (that sits inside the tank from the underneath) and a float inside the tank that has a magnet on it. When the magnet lowers the switch closes and gives you a low coolant reading. Your float could have got jammed down when the tank was emptied. If you really want it working, you can take your tank off and test it with a meter. Turn your tank upside down and check to see if your switch is an open circuit. If it isn't, shake the tank to see if the float moves and check again. If it's still a closed circuit, your sensor is bad. Or............

You can always do the it the lazzy easy way and pull the plug sensor plug off like I did and check your fluid once and a while :iceslolan

Denis