The three lines that go into the fuel pump. this

You have the 1. hi pressure line to the fuel filter and then to the injectors, 2. the return line from the fuel injector system to the gas tank. 3. you have the return line from the EVAP canister at the left rear of the blazer. Note it's common for the fuel line to leak along the frame rail where the lines are clipped on to the nylon brace. Hope this the answer your looking for, the only two lines that is going to have fuel is the hi pressure and return, the EVAP line is vapors from the canister.