The engine room.
Engine Room Combination is a written note found in The Brigmore Witches.
Transcript[]
I've completed the final connections between the mill apparatus and the engine. The power generated should be far more than required to put the mill back into full operation, but I cannot vouch for the reliability of the engine itself. Therefore I am traveling into the sewers to find where the water has been diverted away from the district. It is infinitely preferable to have this water flow restored, which will power our mill in perpetuity.
Should the need arise to reach the engine during my absence, I have set the combination gate to [three digit number].
I will return soon.
Location[]
It can be found inside the locked cabinet in the apartment of Pete, the Hatter mechanic, during the mission The Dead Eels.
Trivia[]
- The combination is variable. See here for a list of possibilities.