Camaro, weird fan thing

2010 Camaro LT 6 speed manual tranny, noted that when my RPM gets to above 2500, that the interior fan speed increases, even when the interior fan is turned off. Its has never done this before. not that I noted but the fan is also more “noisy” when this occurs. Any thoughts??

DC motor rpm is proportional to voltage, and the voltage may be a little higher at higher engine rpm, as the alternator is able to pump out more juice the faster the engine is going. That may be part of the explanation, but doesn’t explain why the fan is running when it is turned off. Figuring that out will probably require access to a wiring schematic.