My Macbook Air (Summer 2011, i7) tends to think it's running way hotter than it is, and permanently ramps up the fan. Closing the computer and reopening resets the mistaken sensor, but I'd rather not have to do this half the time after I open the computer.
I'm using Fan Control for the temperature reading.
Best Answer
The system management controller (SMC) is responsible for controlling fan speeds. This support document describes increased fan speeds as a symptom of SMC problems and how to reset the SMC