you could try checking the wire that runs from the starter solenoid mounted on the starter up to the back of the ignition switch...sounds like the wire is earthing..my old EK did this once..turned on the keys, lights and everything worked but no starter..turns out this wire was broken inside the insulation and to detect it i had to use a multimeter to check continuity of this wire as it gets routed into the loom b4 it passes thru the firewall...on the EK this was a purple wire..as for orange wires leading from the fuse box you mention i think the orange goes to the rear brake light switch on FE/Fc's? it then continues to the brake lights..could be a problem like a wire getting pinched at the rear somewhere..had this happen once as well..fuse kept blowing whenever i turned on the lights..seems the number plate light wire had worn and was earthing occassionaly on the bumper..hope this is of some assistance