This what I recommend, its output is 5 volts NOT 6 volts. My research says to use a 5 volt on Mopar's.
12v to 5v Volt Converter, DROK DC Voltage Regulator Board Power Supply Module, DC 6.3-22V 12 Volt to 5 Volt 3A 15W Waterproof Car Volt Step Down Buck Converter. Over-current protection...