Electrical issue - Battery drain

[avguy]

....The mechanic already did some rewiring to bypass something and the drain is gone but the OnStar will not work in the car. Bill= $108
...
I will definitely try and get the rewiring specs from the dealer (if they will share) and share them here so that others can "fix" this issue.

...found that there is a module under the driver seat, with a white and a yellow connector on it. i unplugged the white connector and the draw is now gone. .....

Sounds like the "rewiring" is so simple that even a stealership can do it.