Here try and see if this helps
This is a write up on how to replace your fuel filter. This goes for Second Generation 2wd, 4wd, 4dr, 2dr, and ZR2 Blazers. It may work for earlier vehicles, but maybe slightly different. The process is similar for most vehicles too.
∙ 16mm open end wrench
∙ 15/16" or 21mm open end wrench
∙ 13mm socket
∙ Pliers (to squeeze front fuel line fitting off)
is to relieve the pressure in the fuel system. There are two ways to do this. Personally I would use the first method since it is easiest and cleanest.
1A Go under the hood and open the main fuse block. You will need to locate the fuel pump relay and remove it. See the pictures below:
Make sure you remember the direction that the relay goes into the fuse block. Next go try to start your truck and let the engine starve for gas. Once it will no longer turn on, the gas line pressure has been relieved.
1B Go under the hood and find the Schrader valve located behind the air intake and throttle body (see picture below). Take a flat blade screwdriver and depress the middle portion of the Schrader valve, make sure to catch the gas that will fly out of the valve with a towel or cup. Once the gas stops coming out of the Schrader valve, the fuel pressure has been relieved.
Second step is to jack up or raise the front of the vehicle and place jack stands and chocks behind the wheels.
Third stepis to start removing the nuts on the back side of the fuel filter. You will need two wrenches (a 16mm and 15/16" (or 21mm) open end wrenches). The larger wrench is just to hold the filter in place and then loosen the rear nut with the 16mm wrench. Once loose enough remove the rest of the way with your hand. Then be prepared with a container to catch the gas (a tin can from having canned vegetables works great).