Radiator cooling fan and A/C questions

06 NB DSG with 5k on it. I have never seen the small radiator fan turn on. I let the car idle for about 20min today in 100 degree heat with the A/C off. This was after driving about 15 miles in traffic. The fan never came on. The A/C works great and is cold but it has been doing this weird thing were when I stop at a light, about 10 seconds later the fan speed (interior) will drop down and then come back up. This is followed by a burst of very cool air. I assume this is the big cooling fan turning on and sucking a bunch of power causing the interior fan to slow down? Is this normal? How often does the small radiator fan kick on when driving in high temps in traffic? I assume that if the small fan is not working then I have not overheated since the A/C is on all the time?? This is my first TDI so I am not sure what is normal and what should make me call the evil dealer...

From my previous experience (not with TDI's) it doesn't take much speed to keep the fan from kicking on. If your driving around town 20-30 mph, there's enough air moving through the radiator to cool it.

In my expierence, the car has to sit idleing for 35-40 mins before the fan will kick on. And it will only run for 10 secconds or so. Remember, the TDI doesn't make anywhere the 'waste heat' as a comparable gas engine.

-Jason

Thanks guys, I guess that does make sense about the radiator fan. What do you all think about the blower fan(inside) dropping in speed and then coming back up every time the A/C cooling fan kicks on? Is that pretty much normal too? I have never run A/C in a car this much. Last time I used the A/C was back up in WA state where the weather never gets above 80 tops...