I left my 2014 Ford F-150 power in with the key turned for about 14 hours. The next morning it wouldn't start so i replaced the battery, still no power. All i hear is fast clicking behind the wheel. Could killing the battery also kill the starter?
Leaving the ignition key in any position (other than "start" of course) has no effect on the starter. The starter solenoid is only energized if the key is held in the start position. I would first check to see if the battery you bought is actually fully charged. With a fully charged battery, and the immobilizer (security) system off - check to be sure the immobilizer is not activated - if the starter motor does not operate at that point, there are only two possibilities: 1) either there is no power to the starter motor/solenoid, or an excessive voltage drop, hence the entire starter circuit would have to be diagnosed; or 2) there is power but the starter/solenoid itself is bad and that includes intermittent operation which does happen. If you desire that a specialist from YourMechanic determine which of these is the issue, and get it resolved, please request a no start diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.