735i - Environmental Control Module - Is there such a thing? Ease/Difficulty?

[Dan in Pasadena]

My brother-in-laws pristine 735i has hot air blowing from the dash when it should not. Easy fix or tough one? Mechanic telling him that to fix it they have to remove the dash? Does this sound correct? Doesn't to me!

Any help appreciated, regards, Dan

[Bear]

Many causes here, one is bad auxilary heater valve, next to fuse box under hood or more common is that the air distribution motor flapper valves (we call the stepper motors) break or fail or they lose a sense of where to reposition themselves at shut down. Sometimes, they will reboot agfter ignition is turned off and yes, if they fail, and there are about nine of them, the dash has to be removed to get at these devils.