Hey thanks alot!I'm on via my phone so when I leave Ill hop on the computer&check it ouy...now if I'm not mistaken from my use of the search button shouldn't this thing have a vacuum solenoid vale.Its a 2000 2dr zr2.I've been replacing the vac lines&I can't find one the vacuum all run straight through a hole in the firewall &there's nothing between the hose&the hole....so idk.If anyone has a picture Id be greatly appreciate it!

Found a pic.

Ok now after looking it seems only blazers with a 4 button 4x4 system has a vacuum valve it this correct?I'm gonna hook some visegrips up to my cable in the morning&see if this thing will go in 4wd if not then maybe the front axle is somehow broke.

 

The 4-button setups used an electronic solenoid, mounted to the firewall near the distributor, to control vacuum to the front axle. The 3-button setups have the mechanical valve located on the transfer case. You have not specified which you have.

If you haven't already found the Tech Article (DIY) section, have a read through this thread:
Common 4x4 Problems

 

Thanks its the 3 button set up.&I did all of my trouble shooting thanks to the link over the past few days.I'm gonna go try to to pull the cable &see what happens.

Ok so this is what I have come up with today,I'm not getting any vacuum coming out of the hose that goes to the vacuum actuator&I pulled the cable&locked it in place still nothing.Now I'm clueless on what's going on any ideas?Remember I said the hoses tuat are going to the switch on the tcase that only one of em is pulling vac.Is that how it should be?

 

Only one of the vacuum lines at the t-case switch should have vacuum so that part, at least, is correct. You need to make sure that the line to the actuator is functioning properly... And that the switch is functioning properly.

 

I've replaced all fo the vaccum line's &put in a new switch already, Ive manually pulled the cable&it still wont engage&hooked up vacuum from another source still nothinglike I said no vacuum from the hose thats suppose to go to the actuator.What else could it be?

 

If you have vacuum to the switch, but not to the actuator, the possible causes are incorrect placement of the vacuum lines on the switch and/or a bad/improper switch.

 

What about that when I manually pull the cable it dosnt lock the front axles any ideas?&thanks for all of the help!Could where the cable goes into the front axle came disconnected in there or could something be broke in the front axle or differential?

 

if the cable gets pulled but there is still no 4x4 then you have bigger problems. when you pull the cable do you feel it engaging at all? like can you feel it click into place?

 

Well if I pull the actuator in by hand I hear a small click which sounds like its coming from the actuator not the axle.I was wondering shoukd I unhook the cable from the actuator &try to pull it farther?Any idea how I would do that?So if its not engaging what else could it be?I'm getting really frustrated the crook who sold it to me said it was fine&it seemed so goy it home&ended up having to pull the head two days later because it had poor compression &the ebcm module was out&now this.

 

yeah. sounds like a rip off. im no professional on this but i think your problem lies within the front axel. does the axle make any grinding noise when you drive it in or out of gear? i heard its pretty hard to bust the gears in there.