6.2l diesel fuel filter housing questions (1990)
 

So i was finishing up my heater core replacement, and after putting everything back together, I snapped a few pictures of some things that

seemed out of place and I don't know where they go, what they do, and if I need new ones.

One is a picture of the top left of the fuel filter housing, open inlet with nothing on it. What should go on it?

Second is picture of a hose coming out of bottom of fuel filter housing, possibly it connects to the top of the housing on the vacant inlet?

Third are pics of a sensor hanging out new the fuel filter housing, no idea what it is, where it goes, and if I need a new one.

Any help? I am new to the 6.2l engine. This is on a 1990 Chevy Blazer 1500 Silverado with A/C.

The open port is for draining water out of the fuel. I think the plug is for your water in fuel sensor but not a 100%.

Those units are notorious for leaks. At the first sign of a problem just upgrage to a aftermarket screw on filter housing.