I have a 1993 S10 Blazer and the 4HI won't engage. I've changed the actuator and it still won't work. It will go into 4LO when I press the 4LO button and it will go back into 2HI no problem. But when I want it to go into 4Hi, I press the button and it does nothing, the light won't even light up. Anyone know what this could be? Any suggestions would be great. And I have the two button setup without the 2HI button. If that makes any difference.

I think I found the problem. I pulled the fuse and then put it back in and tried the 4Hi and it worked. So I restarted and tried it again and it didn't work once again. I read in another thread very similar to mine and he had to change the selector switch. I'll try that.