Hey i have a 2000 blazer Ls 4x4 5speed I just took on trade. That being said I can't get the 4x4 to work I replaced the vacuum switch and 4x4 switch inside it's the 3 button one and checked vacuum lines found one off on top of bell housing it's really short about 6inches long and comes off a plastic T thing so I just plugged it for now.. But apparently the guy that had it removed actuator under battery and converted it to a manual switch you pull it and then lock it into place. I can here The 4x4 engage in the transfer case in 4hi and 4lo but it's not locking the front up. I've been trying for a couple of weeks to figure it out and can't so please help. Thanks

 

Welcome to the forum. Not sure if plugging that hose was wise. There is a vent tube for the transmission and transfer case (could be the T fitting you described) that runs across the top of the transmission to the engine compartment. Follow that rubber tube to make sure you didn't plug the vent. I'm wondering if it's the vacuum line by the master cylinder. That connects to a reservoir in the fender.

There is a company called posi-lok that makes aftermarket cable operated front differential engagement systems to replace the factory vacuum /diaphragm system. Many have tried to duplicate that system with home made choke cable contraptions. Search the posi lok system to see if that's what you have or something else. We can help if we know how it's been altered from factory.

 

Well the line I plugged its right on top of bell housing with the other 3 vacuum lines it's bigger than the vacuum lines but comes off a t fitting and it's like 5 inches long I couldn't find where it hooks up and I know it has to go somewhere cause. I know which line runs in the fender to the reservoir it was off too and what I've read you can plug it and be fine. But I think I've got a home made system it seems to work fine tho I took the actuator off the front diff and checked the cable and it pulls in good. I'm just stomped I know it's something simple..