Is the light under my side mirror acting weird?
 

This should be easy to answer :)
The light under my 02 Taurus' driver's side mirror stayed on after I shut off the car, the went out after about 10 minutes. It did that twice so far. Does it always do that and I just haven't noticed? Or is there an adjustable timer for it? It was just brought to my attention (after my friend replaced the battery, if that matters). This car makes me paranoid...
Thanks!