antec ps fan not spinning

[ron2368]

I have an antec truepower 450 that came with my antec case, its about 2 years old not used much. I have no overheating problems that I can tell.( could be smartpower, cant remember)

I noticed that only the inner fan is blowing, the fan at the rear grill on the outside of the case does not move. Is this fan supposed to be running all the time? Or does it run at a certain temp? What should I do ? thanks

 

[7earitup]

I dealt with a few computers that had Antecs in them and the back fans did not spin on those either. I think they only turn on at certain temperatures or loads.