2002 Ford Explorer

Tires and Wheels problem
2002 Ford Explorer 6 cyl Four Wheel Drive Automatic 117000 miles

I cannot get the 4wd on my explorer to engage. I press the buttons and nothing happens. No lights come on, nothing. I know that the lights on the dash are working because when the car is in acc, the 4x4 low light pops on for a few seconds. I've read the owners manual, and had a friend check the corresponding fuses, and found nothing wrong. I'm in the middle of a blizzard and I could really use my 4wd. Any suggestions?
February 10, 2010.

Where you need to start is at the transfercase. Threre is an electric actuator that shifts for transfer case from 2 to 4wd when you push the button. You need to see if that is getting power. Check that and let me know what you find.