I've been reading through the "GMLAN SW-CAN Message woes" thread, and I'm a bit confused and hoping someone can set me straight:

Is it the case that OBDLink needs a (not yet released) update to work with GM SW CAN, or just that without it extra steps are required to go back and forth between 29bit and 11bit mode, or is it that you have to hand-build the requests out of bit masks?

For example, in that thread they're talking about controlling the GM door lock module, but I thought (until now) that it should be as simple as setting the CAN id to the ID of the module, sending the command, and you were done.

Obviously I have a few mental gaps here, if someone could take a step back and give me (and anyone else lurking) the 2-minute "what I need to know to understand this issue" I'd sure appreciate it! Particularly in terms of reverse engineering GM CAN commands and then sending (or 'replaying') them back to those modules.