Finding the door in Control the Foundation DLC is a bit tricky when you are in the maintenance area / restricted area. This guide will help you locate the hidden door in the maintenance area by explaining how to find in Control The Foundation DLC.
How to Find the Door in Maintenance Area – Control The Foundation DLC
Before you start the mission you need to speak with the board located Hotline Chamber. On the top left of your screen, you will see the missing objective, “talk to the board.” Under the objective the area of the objective is mentioned, “executive/hotline chamber.” Use the TAB to open the map for a better idea of where you are. Go up the stairs and head left and then turn left again at the end of the road. You need to go through the Director’s Office and then take right, and the next left to reach the central executive area. Once you are at the central executive area you need to find the hidden door in the maintenance / restricted area.
Find the elevator on the way of Sector Elevator. Select the maintenance sector, the location will be on your map. Head to any fast travel point and choose The Foundation or you can follow the path to the restricted area. When you get there via fast travel, go left you will see a black door. Enter and continue another mission called Explore the Foundation. The black door is what you are looking for.
This is how you find the hidden door in Control The Foundation DLC in the maintenance area. If you need more help with the game check out the Control Wiki.