The Electrosensitive Bulb is one of the malfunctioning lights Dylan repairs during the Maintenance Protocol side quest in Control Resonant. It hangs in a facility room deep in the Underpass and flashes violently with bright white light because it cannot tolerate any electrical source nearby. Until every battery around it is gone, the interact prompt will not appear.
Quick answer: Remove all three orange power core batteries from the bulb’s room and platform by throwing them into the surrounding chasms. Once the last one is gone, the light steadies and you can press Square to fix it.
Where to find the Electrosensitive Bulb in the Underpass
Track the Maintenance Protocol quest and open the Underpass map. The objective marker for the Electrosensitive Bulb sits within the Underpass area, flagged by the yellow diamond marker with an exclamation point on both the HUD and the mini-map.
Follow the marker across the concrete architectural blocks, climbing to the higher ledges. Reopen the map along the way if you drift off course, then continue toward the open facility room where the flashing bulb hangs from the ceiling.
Why the bulb keeps flashing
When you enter the room, the Maintenance Worker speaks over comms and explains the problem. This bulb does not play nice with other energy sources, and before the appeasement ritual can happen, nothing electrical can be sitting close to it. Batteries and generators give it a headache, which is why it flashes so aggressively.
The fix is simple once you know the cause. Clear every power source in the immediate area and the bulb settles down on its own.
All three power core battery locations
There are exactly three orange power core batteries to remove. Two are inside the bulb room and one is on the exterior walkway just outside it.
| Battery | Location |
|---|---|
| First | On a movable cart/trolley inside the bulb room |
| Second | Against the right-hand wall inside the bulb room |
| Third | On the exterior upper platform beside the electrical gear |
How to remove the batteries and fix the bulb
Throw each battery into a distant pit or shaft rather than just setting it down nearby. The bulb reacts to any power source in its vicinity, so dropping one too close can keep it agitated.
How to know the bulb is fixed
When the repair registers, the Maintenance Worker expresses relief over comms and the quest updates to Complete the Final Step at the Projector Room. That objective change is your confirmation the Electrosensitive Bulb is done.
Return to the first projector room now and complete Maintenance Protocol. Check the Quest Log; its completed-step entry confirms your progress before you continue.
