Why is my 2013 Dodge Durango key fob not working?

If the key fob is not working then You need a new battery. All key fobs use the same type of battery, which is a cr2032 battery. These are small coin-shaped batteries and they will cost You about 5 dollars each on average. You can find them in the same place You would normal batteries. To change the battery You will need to remove the back panel of the fob. Some fobs are different than others. You may be able to simply pull down on the back and have the piece slide off. If so then You can simply remove the old battery and put the new one in its place. However, You may need to remove a couple of tiny screws before You can do this. They are not hard to get out, as long as You have a small enough screwdriver on hand.