My daughter's '99 Mustang GT intermittently displays the low coolant warning light even though the radiator and coolant recovery tank are full. The car never registers any higher than the mid-point on the temperature gauge. Any ideas what might be the culprit? I'm not sure if a '99 has a coolant tank sensor. Thanks!

 

My '00 Contour does this also but there is a known cure. The sensors are a float type that activates a magnetic switch, add coolant to the overflow tank about 1/2 or more pass the max fill line keeps them happy for some reason. It was a problem for some Fords around this time frame. If this doesn't work then either check the plug or you have a bad sensor but this is a common way to fix this including myself have cured the light this way.

 

My cobra does it. The float in the tank is probably isn't "floating" as well as it used too

 

So I assume the only "cure" is new tank?

 

My 1994 mustang gt had the same problem. I replaced the water reservior bottle cap with built in low coolant sensor that I got from a junk yard. Problem is now gone!