Replaced neutral safety switch starter still tries to engage when clutch pedal is engaged

1995 chevy s-10 pickup 2.4l 4 cylinder 2wd manual transmission 1995 chevy s-10 pickup 2.4l 4 cylinder 2wd manual transmission

Since it only tries to start with the key on and the clutch pressed, that indicates that there is no short to ground since the area involved is the hot side of the circuit. There is a starter relay in the circuit, but if it failed open, you would get a no-crank condition. If it failed closed, the starter would run continuous until you pulled the fuse or disconnected the battery. What most likely has happened is that the ignition switch itself has malfunctioned internally, applying voltage to the START contacts when in the RUN position. Since it only tries to start with the key on and the clutch pressed, that indicates that there is no short to ground since the area involved is the hot side of the circuit. There is a starter relay in the circuit, but if it failed open, you would get a no-crank condition. If it failed closed, the starter would run continuous until you pulled the fuse or disconnected the battery. What most likely has happened is that the ignition switch itself has malfunctioned internally, applying voltage to the START contacts when in the RUN position.