Arid Badlands (DLC4): Weapon Crate Locations

In total there are 11 chests in the Arid Badlands (DLC4) area.
 * 9 Red Chests
 * 2 White Chests

Location 1 (2 Red Chests)
This is the transition point, before the gate. There are 2 Red Chests and numerous ammunition crates here.

Location 2 (7 Red Chests, 2 White Chests)
Go through the gate, and simply go around the perimeter of the map. Going near Marcus' bus will trigger the cutscene and the MINAC fight. You can still loot all these chests after the fight.