Ok Folks...the best way to describe this is that it is as if somebody reaches over and turns the ignition off...dash lights ho crazy...headlights go out...and it is getting really scary. I drive a 2008 jk 4dr ...

 

First place to start is all the connections for the battery and ground wires.

Both battery terminals clean and tight.
Positive lead at the fuse box clean and tight, both ends.
Each ground connection from the battery clean and tight, both ends.
Lead from the alternator clean and tight, both ends.

Have the battery tested.
Have the alternator tested.