Ok even tho i dont own a Suby at all lemme see if i can answer this for ya. The DCCD would be right behind the shifter, it should be a wheel switch. That allows you to split the power between 65% rear and 35% front, to 50-50. That should also solve the question you have about the arrows on the cluster, they should move when you roll the DCCD.
The outside tempature may be in Celisus but i have no idea on how to change that you would have to ask someone who owns the car.
hope that helped