My 2000 Vienta Grande has automatic air con, you dial the temperature and it selects the most suitable fan speed and air flow accordingly. SInce picking up the car from a service yesterday, the fan speed is going up and down erratically. This seems to be happening more when the temperature is stabilizing at the dialed temperature, rather than when it is going full pelt trying to bring the temperature down from high. You can actually see the temperature blocks in the LCD going up and down. Also you can hear the fan revs going up and down - sometimes more so than others. The service guys are saying they didn't change anything apart from minor service and replace starter motor.
Any Ideas?