I think it is the other way around.

The trailer module just works the lights. Everything else is done by the vehicle, if it sees a trailer module. Things like TSC are included in the DSC system, just waiting to be activated by the presence of a trailer module. I don't know why a trailer module that is also used on an E83 and an E46 would have anything in it to control ride height or brakes, but perhaps there is a bus signal to tell a new system that the trailer module is there and to take the appropriate action when a trailer is connected.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue