I have changed the fuel pump and checked the red switch and 94 ford explorer won't start?

Relay fuse is working also

Have you sought professional help?

On a '94 model there could be many reasons for a no start condition besides a bad pump, relay or tripped cut-off switch. Can we assume you can't hear the pump when you turn the key to the run position before starting? If that's the case its likely there's a short or a break in the wiring between the ignition and the pump. If you can hear the pump have you checked the fuel filter? The only way to determine exactly what's causing the issue is to eliminate every possible cause one at a time.

Remove the air intake hose from throttle body, spray starting fluid or carn cleaner into the tb opening, reattach hose, try starting engine. If it starts, runs for a few seconds then dies, you have a No fuel problem. If it didn't start at all, you have a No spark problem. No spark could be caused by a fuse, relay, pip sensor(inside distributer)ignition module, or ignition switch. No fuel could be caused by bad fuse, relay, pump, defective fuel pressure regulator, or no injector pulse. If the fuel pump turns on for a few seconds, shuts off, then runs again while you're cranking the fuse, relay, and pump are probably ok since the pump is new. Try flooring the gas pedal then crank engine at the same time. If it starts and runs, one or more injectors is leaking or stuck open. If fuel pressure is 0 or really high, the pressure regulator is most likely faulty. Now test injector pulse.Disconnect a fuel injector harness from injector, attach test light across harness terminals, crank engine and make sure light flashes