the starter has a solenoid which is usually powered by the smaller of the two wires leading to the stater, take a multimeter to this wire using a steel bolt e.t.c as your negative get someone to turn the ignition on and check for a feed thus elimanting any ingnition fault. if your solenoid is receiving a feed it may need replacing the metal contacts within these often rust and snap try checking these.
naill
August 2009