2001 mustang won't turn over

Check the fueses in the engine bay and driver's kick panel. Especially F2.6 (20a) in the Central Junction Box (CJB). The CJB is located in the driver's kick panel.

There is also a starter relay in the engine bay Battery Junction Box (BJB). Can you hear it click when you try to start? If you can hear the relay click, this proves power to the relay as well as the clutch safety switch and ignition switch.

If no relay click, the problem is in the ignition switch, clutch/transmission safety switch, fuse, or in the relay itself.

If relay click, the problem still could be in the relay itself or in the wiring. Power goes directly from the starter relay to the starter solenoid.