There is so much 12 volts back there it hurts. All kinds, every kind, come one, come all, get your 12 volts on.
Need lots o' current at all times ?: tap the DCDC's giant positive lead. You can't miss it.
Don't need lots of current, but still want 12 V at all times?: WHT/RED @ MCM pin B10 (there's only one back there with that pattern)
Need it whenever key is on?: BLK/YEL @ MCM pin A09 (there are other BLK/YEL, so make sure you've got the right pin)
Need IMA hold? (key on +10s after key off): PNK/BLU is your guy! There's two back there with this pattern and they're both the same... use either one.
Need 5 volts (and not a lot of current)?: GRN/WHT @ MCM pin C24. Make sure you pick the correct one.
Need something else? Post up and we'll find out.