ok im 16 and havent even got to drive my blazer yet cuz im waiting on my new fuel pump to come in. but the previous owner(who i have know for ever) said that the 4x4 wont engage. he said that the lights saying its working will come on but it wont engage like i said. i need help!!!!! ... let me know thx

 

Have you even TRIED searching yet?

 

There are many threads on this as rastoma alluded to. Search a little and if you come up empty there is plenty of help to be had here.

 

Yes, the people are great and will try their best to help.

But you gotta search and narrow down the issue. Just saying your 4wd doesn't work is too broad of a problem.

I too have been having 4wd problems.... just doesn't work. No lights on the switch unlike yours... wish mine had lights show up on 4hi/4lo, I'd have something to go on and a path to follow.

Try and narrow down the parts that work and those that do not then list those steps you've taken and you'll get a lot of people offering to help narrow it further.

 

theres a few different things that could go wrong to not make the 4wd work.

1. transfer case switch is common to go and can easily be replaced for around ~$25
2. vacuum line could be bad somewhere. check the pressure at the "ball like container" under the hood to see if your getting suction.
3. the actuator, which is under the battery tray or around there (depends on yr), sometimes won't engage. check to make sure that it is engaging.
4. if all of these are good and it still doesnt work then something in the front diff might be stuck/bad. just take the 3 bolts out on the shaft on the passenger side of the front diff (shaft that comes off front diff) and pull on that to try to loosen things up.

the first 3 didnt fix my 4wd when i had a similar problem, lights came on but no 4wd, so i attempted to take apart the front diff and by pulling on that cable in that shaft coming off of the front diff it loosened something up and my 4wd went back to working

heres a parts diagram of the front diff:


part #10 is the cable that i'm referring too