While there are conflicting reports about the logic of the intercooler pump. With mine it didn't run all the time (you can hear it before she comes up to speed), and with this mod it did. With this mod you get lower IATs. Check out here: https://mbworld.org/forums/w212-amg/785054-reduced-iat-s-pump-rewiring.html
I've heard a report on the AMG subforum that the IATs reduce with the always on mode but the overall power decreases when running the IAT to always run like this as the ECU "wants" to control the pump.
I have taken the always on mod off for winter, and she seems to drive a bit better.