ACC....

[f5fstop]

Not going to slap you or anyone. I sort of figure you might be talking H2 when mentioning the fuse panel. I just wanted to make sure no one taps into the SDM, now that is a component that can do a lot of damage.
Yellow has been common for ACC on GM's for many years, and now instead of coming off the ignition switch to many accessories, it comes from the RAP relay, turned on by the BCM. Look at all the GM schematics on the eSI system. (In fact my corvettes have a three wire bundle just above the BCM; one black, one yellow, one orange for connecting accessories. We normally like to say those were designed in for a radar detector.)


As for tapping into databus components, normally not a problem if low current draw, and you are only tapping in for power. As long as you don't try and tap into a bus line, or the ground side, everything should be ok.
If installing a large current line, just connect to a yellow for a switch side of a relay, and run the power circuit directly off the battery B+ side.
To tap into something like the wiper motor, just tap in far down the line. If done correctly, you will not be cutting power to the component, and if it fails, a tech will check at the component for power, find it and move on to other diagnosis.