My four wheel drive does not work!

What is your question?

I have a 2003 ford explorer xlt. My four wheel drive does not work, I push the 4x4 auto, and the 4x4 high buttons but nothing.My 4x4H dash lights blink 10 times then stops.Five to ten minutes later it blinks 10 times again.I haven't tried the four low yet.I still drive the truck, only the back tires spin...I would like someones knowledge on this issue if possible. thank you much..Ray