My a/c button wouldn't lite up and only minimal forced air (warm to hot) out of the vents when fan control knob at maximum. BMW service determined that: "15049 IHKA in transport mode IBSP (D.S.)," and reset to proper code. Now the question is how did the a/c get into transport mode? The only thing I can relate as possiblay causal is that I recent changed the car's battery. Any thoughts?