After repairing Generators for a total of 33 percent, Wiretap activates:

After repairing a Generator for 3 seconds, press the Active Ability button to install a Wiretap, which stays active for 60/70/80 seconds.
The Auras of trapped Generators are revealed to all Survivors in yellow.
When the Killer comes within 14 metres of a trapped Generator, their Aura is revealed to all Survivors.
Damaging the Generator destroys the Wiretap.

Failing a Skill Check while repairing:

Prevents the Generator Explosion.
Applies the default Regression penalty.
Applies an additional Regression penalty of 5/4/3 percent.
Technician reduces the audible range of your Generator-repairing noises by 8 metres.

In your countless years in The Fog, you have seen it all, and when you are focused, you can remember most of it too. Succeeding a Great Skill Check while repairing a Generator reveals the Killers Aura to you for 4/5/6 seconds.

Reduces the volume of Grunts of Pain while in the Injured State by 25/50/75 percent.
Iron Will cannot be used when suffering from Exhaustion, but does not cause the Exhausted Status Effect.