[81montedriver]

I have a 95 Blazer LT as well and I have the exact same problem. This first happened a year ago and my mechanic replaced the vacuum actuator. The problem appeared again a week later w/ the same problem. The 4hi wouldn't engage and my 4wd lights weren't on. Only 4lo would work. Anyways my mechanic told me to disconnect the battery as to reset the computer and it worked. This problem has happened a number of times over the last year and the battery reset has fixed it. The latest time it didn't work was recently in the middle of a snowstorm! I had to reset the battery for 5 minutes but it worked again. This seems only like a temorary solution though.