If he pulled the connector to turn on the fan all the time, he did not unplug the pressure sw, he unplugged the temp sensor for high fan .
..and if he did not get the lowfan to come on after the recharge , there is a possibility he has not gotten a complete chage in the system to trigger the pressure sw for the low fan.
Jumper the two leads at the pressure sw at the drier [ the two pigtail wires]
See if low fan comes on.
High fan has probably now blown the load fuse .
http://catalog.worldpac.com/mercedesshop/sophio/image.jsp?title=Relay&url=http%3A//img.eautopartscatalog.com/live/P202070194OES.JPG