The factory security light on the dash has nothing to do with the alarm system (either original or Clifford). It is part of the VATS Pass Key II system that checks the resistor pellet on your key to ensure the correct key is used to start the car. Usually, the problem is caused by dirt and grime on the contacts causing an increase in the resistance so the system thinks the wrong key is inserted. It can be solved by using your spare key or cleaning the contacts on the key with a pencil eraser and some rubbing alcohol. Sometimes you need to clean the contacts inside the ignition cylinder by spraying some contact cleaner (Radio Shack) into the key slot.
White 2000 Trans Am (sold)
White 2011 Mustang Convertible
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