We have 2001 F150 that will not start.

check battery voltage, should be 12.4vdc. If battery is good and still won't turn over, check all battery cables for corrosion and make sure they're tight. If all cables are ok, check for voltage at the starter solenoid small terminal. If voltage is present and still no crank, replace starter again. If no voltage present, check starter relay in fuse box

Thank you irodn911, I will check it tomorrow and let you know. We replaced the battery first then we checked the starter and replaced it but that doesn't mean it was good so will check it tomorrow and the fuses. Thanks, Joyce