Hi I have an s500 V8 petrol year 2000 model. I get no air from the centre vents at the front. I can control the temperature and all other vents blow okay. If I interrogate the unit I get three codes KLA A 1271, FRA A 1429 & FRA V 1429. If I try to delete them the unit says it has deleted but then won't do anything at all unless I restart the car. Then the codes are back. Any clues?