The fuel filter is located on the left side of the engine just in front of the drives seat under the hood. In the 93 Hummers is was not placed in the idea place, but with a little effort, you can get to it and do what is needed.
When replacing the filter, you will need purge the sir out of it while starting the truck. Otherwise you can get a jump wire and start the fuel pump until you get all the air out of the filter before starting your engine. My option, it is a pain in the butt, some one should have added a simple button under the hood to turn on the fuel pump to get he air out. Good thing you don't need to do this too often.
The filter will only go all the way down in one position, and make sure the seat is clean before putting in the new filter.
Filter shown in the correct place before the black ring goes on to hold it's
seal.
WIX part # is WIX 33376