Subaru Repair: 02 Forester revs w/ fan - AC, air conditiong, engine control module

Question
Hi, not sure if this is a small issue, but occasionally the engine revs extra 500 RPM when fan or AC is on even when braking, no problems when fan is off.  Performance is always  delayed when the fan is on, have to accelerate more, usually just don't use the fan, never noticed the excess revs until about a month ago.  Had the car 5 years, no problems yet.  Thanks,

Answer
Hey Kevin,

It's hard to say if what you are feeling is something to worry about or not.

A 500rpm increase with the ac on is excessive.

How it works is that when the computer turns on the cooling fans, air conditiong(which also comes on with the defrost) the computer also increases the rpms to compensate for the load.

I am guessing that there is some reason that the ECM(engine control module) is putting the rpms where they are.  

I would suggest a diagnoses by someone familiar with Subaru.

Justin