Question : Problem: Macbook pro fan speed constant

Hi,

I have a 17 inch macbookpro which i have recently added a new hard drive to. It seems that no matter what i do my fans are constantly at 2000 RPM.  All of the temp sensors seem to be working.  I installed an app to control the speed manually and the fans respond accordingly.  My question is, does anyone know what/where the sensor might be located that is responsible for controlling the fan speed? I purchased my computer around 2007

Answer : Problem: Macbook pro fan speed constant

That doesn't tell me the model.
I might not be able to do anything with the model number but I definitely can't without one.