well i went to put my blazer in 4wd and all it would do is the 4hi light would blink and wouldnt do anything. the wheels wasnt engaging at all. im sure this subject has been beaten to death, but its winter time and i def need this 4wd to be working. so can anybody please shed some light on this for me or point me in the right direction.

 

Start with the 4wd related threads in the section linked to below:
Tech Article (DIY) Index

Let us know if you have any questions not covered in there.