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changed the starter solenoid worked for 1 week then same problem
A low battery or hard to turn engine will draw more Amps than normal and can weld the solenoid closed.
Pull the wire off the "S" terminal of the solenoid and if it still cranks the solenoid is welded closed and you will have to replace it.
Not all solenoid are made of the same quality, make sure you get a good one from Ford or NAPA best.
If it does not crank with the wire off the solenoid then look at the Ignition switch.