My wifes 2005 e320 cdi has an interesting problem other than throwing some charging and voltage codes it will display ABS ESP visit workshop only when the car is in the rain. When the car drys up the messages go away. It does not seem to do it after the car wash (handwash). I do have a code for the right front wheel sensor but I cleared it and it has not come back. The car also shows aux battary defective and open relay or fuse in aux battery system. The main battery is brand new and the the BCM has been updated by the dealer. The aux battary is original but shows 12 v resting. any advise? Do I have two problem with the rain and abs esp lights being one and the two battery system being the other... Thanks