2006 Corolla - fan runs a lot - should it?

Start the car and the fan runs for a short time then goes off, drive down the street to the stop sign and the fans comes on (for 15 seconds or so) and goes off - it keeps repeating this cycle. Is the fan supposed to run this often? IF not, anyone know what the problem might be?

Most vehicles have the cooling fan active when any A/C setting is selected. The fan will cycle as you describe, usually longer than 15 seconds tho.

In addition to A/C which will run the fan(s) at full speed, the coolant temp sensor determines when the engine cooling fan will turn on -- in warmer weather you are likely to see the situation you describe -- while you're moving, more air will be passing through the rad and the coolant will be circulating faster (lowering the coolant temp), so the fans will not be necessary, but when you stop moving, or sit in traffic, you and the coolant won't be moving fast enough (and the ambient air is warmer anyway) to maintain that optimum coolant temp, and the fans will turn on until the coolant temp lowers -- this can take a very short time, and it's not a problem.

Basically, the fan runs when it needs to -- whenever that may be.