Low Coolant light

I've got a low coolant light that turns on and stays on most of the time i'm driving, occasionally turning off after a good while (at least 20 miles, but sometimes more than a 100). I know theres been problems with leaky manifold gaskets, but mine's been replaced, and is not leaking. The radiator is full of coolant, and so is the resevoir. The van does not over heat, and has not used a drop of coolant (as measured from the level in both the radiator and overflow tank) in the two weeks since I've purchased it. When I open the radiator (motor cold) cooland comes a drainin out. Could this be a bad sensor, and if so where is it located? I also thought it could be a problem with the radiator cap not functioning, causing a lack of pressure at operating temperature? I'm gonna replace the cap today, but anyone got any other ideas?

I had the same problem in my 98 venture and after flushing the radiator with Zerez radiator flush the problem went away. Flush it many times to clean the gum from the sensor, I don't think you need to replaced it. Good luck

i'd say its a bad sensor. The sensor is on the passenger side of the radiator. Its a 3" square plastic piece thats a b!tch to replace.