I recently bought a 2014 E-350 12 passenger model. While driving at highway A/C blows cold. When I am in traffic or stopped and at idle the air blows only a few degrees cooler than the outside temperature. I brought the van into the dealer to have the system serviced and they told me that this is a known problem for these vans and there is nothing they can do to fix this problem (this was after they had the van for four days and replaced the condenser and recharged the system). After talking with a few mechanic friends I was told that it was either the fan clutch or an expansion fitting before the evaporators. If any one has any ideas or input please help me.

 

Considering the conditions of your complaint the first consideration would be to have another dealership check the vehicle for you. Something like this should be covered by the vehicle warranty.
You might like to check the following U tube presentation by
FordTechMakuloco, Quick tips#8 ,poor a/c performance.
Should help you to learn a little about the system.