I owned a 2003 bmw and there were many modules within it (for example, the rear trunk latch was its own module). With CAN bus electronics it’s super cheap and t

I owned a 2003 bmw and there were many modules within it (for example, the rear trunk latch was its own module). With CAN bus electronics it’s super cheap and they design a lot of the parts to operate this way, and they don’t directly interface with the ECU. They could have a relay in the ECU that provides the power output to the heater wires and it will only operate if the CAN command has a signed payload that uses some key from BMW, and compromising that key or sharing it would be in violation of the DMCA, similar to the Sony PS3 key that happened many years back [0] or the current battleground of right to repair John Deere tractors. That would make it not technically impossible to create another replacement part, but it would violate copyright. [0]: https://en.m.wikipedia.org/wiki/PlayStation_3_homebrew#Private_key_compromised https://en.m.wikipedia.org/wiki/PlayStation_3_homebrew#Priva...