Chevrolet 2500 Not Running, May Be Fuel Filter Sensor

That red wire is only for the fuel heater.will not cause a no start.try pumping the primer pump on top of the fuel flter hsg. but first open the bleed screw,which is black plastic also located on the top.this will eliminate any trapped air that might have entered the fuel intake system.if the pump does not get firmer and harder to push, then you have a leak in the fuel supply lines or the ck valves in the fuel filter hsg or stuck open. Still no start have it scanned to ck fuel pressure while cranking.it should be close to 5000 lbs