Q: When turned to the "On" position, there is a clicking noise as if there's a dead battery.

Hello and thank you for contacting YourMechanic. Check the connections from the ignition switch to the starter. It seems to me like there is a short within the ignition switch making the starter engage when the ignition switch is selected on the on position only. The starter solenoid should not engage unless the ignition switch is on the start position. I recommend replacing the ignition switch. If you need further assistance diagnosing the hard start, a certified professional from YourMechanic can come to your location to perform necessary repairs.