I've got a 1985 chevy k10 silverado with a 6.2 and the water in fuel light won't go off. The other day I took my dash cover thing off and noticed that there was no light in the water in fuel socket (this truck is a couple months new to me). So I put the light in, and when I turned the truck on the light came on. Now according to Chilton's, "the light will come on for 2-5 seconds each time the ignition is turned on, assuring the driver the lamp is working. If there is water in the fuel, the light will come back on after a 15-20 second off delay, and then remain on." Now I changed my fuel filter and opened the water drain valve before (I have the square body filter) and it didn't seem like water came out. So I put a new filter in and the light came right back on... Judging by the light being taken out, and also not going off from seconds 5-15, I assume that the sensor is bad, or that somewhere a wire is chaffing... What do you guys think?

 

Sounds like you are on the right track-something is grounding out the circuit to illuminate the light.