I recently converted my "95 F-250 to run on VO. So far, so good. I am using a basic gravity filtering and dewatering setup. Using a pan test, it appears my VO is dry, but I am paranoid because I know what water can do to the engine. So my question is where does the "Water in Fuel" light sense the water? Is it in the diesel tank or further down the line - meaning, will it light up if there is water in my VO? And how much water will cause the light to come on?