I disagree (respectfully)) with 400E about the fans coming on to protect the compressor. For the AC to work the condensor needs air always flowing across it. When my fan wasn't working the AC didn't cool at all at a stop .
There is also a thread from a physist with too much time on his hands about lowering the temperature the fans come on. The temperature was set by the EPA to keep the smog down, cooler engines are dirtier, but when its 100 out...
And I was considering looking into a way to have the electric fans stay on after the engine is shut off to keep things from cooking under the hood. I thing things get hotter right after the engineis shut off and cooling them a little would make stuff last longer.