My 4x4 high and 4x4 light will flash when driving about 3 times,but when I try to put the truck into 4x4 I'm not getting any response it was just working the other day so I'm not really sure what it is,any help would be appreciated

 

There is a good video that should help explain what is or is not happening.
Go to; "fordtechmakuloco 94-2004 ford4x4 inoperative in depth diagnosis".
I think he does a good job of explaining it. Let us know if this was of any help for you.