Had the dealer replace the TCM a few months ago to fix a check engine, jerky trans, power steering light issue. That's what the codes said was the problem, but it didn't fix it. I now wonder if it's the BCM. Where is it and how easy is it to extract from a junked car? Is it really the "central brain" that could be throwing off many seemingly unrelated electrical issues? I know it has to be programmed (isn't GM wonderful?), but I don't at least want to pay full price for the part.