'94 Ford Bronco

Hey guys-
I've been helping a friend of mine do some maintenance on his '94 Ford Bronco with a 5.8 liter motor. We were wanting to change his fuel filter, but have been having trouble finding where to depressurize the fuel system?? I saw some type of Schrader valve looking thing on top of one of the fuel rails. It almost looks like a valve stem with threads on top, and what looks like a needle valve inside of it. I haven't tried pressing on the needle with a screwdriver or anything, because it's not my vehicle & I don't want to mess anything up. The owner of the Bronco has a crappy Hanes manual for us to refer to, but it's not much help. That particular Hanes manual covers Broncos & F-series trucks from 1980-1996. So that is a lot of info. to cover in such a thin manual. But the Hanes manual does show an inertia switch that is supposed to be inside the car, on the firewall, right to the left of the brake pedal. Well, there isn't one. We even checked the firewall in the engince compartment, just in case it was in there. Couldn't find anything. I've taken apart many Ford fuel systems and have the appropriate fuel line disconnecter tools that push the spring out of the flanged fuel rail fittings. Please let me know if you guys can help me with depressurizing this '94 Ford Broncos fuel system. It would be much appreciated.

Simi-