1989 blazer will not shift into 4x4 high or low?
 

My 1989 blazer will not shift into four highor four low it acts like the linkage from the shifter is disconected the lights on the four wheel drivew display doesn even read that its trying to engage into four wheel any suggestions on what the problem could be or if any one had any problems like this feel free to share thanx.

RE: 1989 blazer will not shift into 4x4 high or low?
 

Hi, I'm new here, and i have an 89 S10 blazer with the same issue. you may never read this, but i'll post it anyway. after a good amount of research, i found that the spring/pin/clip that holds the actuator cable to the fork on the front differential (i believe they call it a "differential locking spring") is probably worn. i was originally told to check the cable itself, to check the actuator under the battery, and to check the vaccuum pressure. all turned out good, it was not until i took apart that part of the diff that i found the issue.

RE: 1989 blazer will not shift into 4x4 high or low?
 

A faulty spring in the front axle would not prohibit the transfer case from going into any of the 4wd modes. 4LO would still be very noticable due to the gear reduction once engaged.

Have you had someone move the shifter while you watch the linkage underneith? It could be that a cotter pin has come out and the linkage is no longer engaged on the transfer case...