I have had my car serviced and I asked them to have a look at my ac as only one side of the vents was working so the plugged it in and the error code was B1903 LH mix feedback ! He was unsure what it was and so am I. Has anyone else had this problem or knows what it is ? It isnt a big problem but I would like to get it sorted since England is having some decent weather

Sounds like duff actuator on the Climate Control unit possibly.