What does the body control module do, if it even exists?

The Body Control Module may have an effect on the Heating...the most likely problem is a faulty auxiliary waterpump/heater valve. As far as the transmission not shifting...that could be a lot of different things, from low fluid, defective parts, clogged heat exchanger. Have a good quality BMW Specialist take a look at it. Kind regards, Stephane Grabina BMW Excluservice Rockville, MD 20852 www.bmwexcluservice.com