I have a 95 jimmy and my 4x4 doesnt work. I am not getting any vacuum to the actuator under the battery tray. My vacuum lines looks fine (no dry rot). I have replaced the vacuum switch, the switch inside and i had a new encoder motor put on. My 4x4 wont even try engaging unless im in neutral and not moving and even then both the 4 hi buttons and the 4 lo buttons flash and then it goes back to 2 hi.

Any help would be greatly appreciated

 

Please try the SEARCH feature. It sounds like a vacuum line isn't hooked up somewhere. It does not have to be in direct connection with the 4x4 actuator, any vacuum leak on these vehicles cause huge amounts of issues.