Electrical problem
2001 BMW M5 6 cyl Four Wheel Drive Automatic 72000 miles

I have a problem with heater blower, and have checked the fuses both are fine ,the entire ac, and automated heater system is completly electrical no manual knobs to turn , all electric switches work and light up but no air being blown , changed the battery 2 weeks ago the garage i bought it from said they put a new battery in when i first got it , but it failed at the first sign of winter ,it turns out they put a mondeo battery in which was not man enough for the car would that have caused any problems ,i still have 9 months warranty from the garage m4 vans but thought i would try this first ,hope you can help