I think I've got a new one for everyone here...

I've got a '94 S-10 Blazer, 4.3L W code, auto trans, 4x4

The issue is, when I go to shift into 4hi nothing happens, but if I shift into 4lo while in neutral it shifts into lo just fine. When I hit the 4hi button, only in neutral, the lights blink a couple of times (two or three), but nothing happens. If I'm in any other gear, I don't even hear the normal click that goes with pushing the button.

I also had an issue getting it out of 4lo last weekend. The 4hi worked when I pushed it a week ago, but didn't when I went to use it about an hour later, however 4lo worked fine except that it didn't want to come right out.

Any ideas?

 

I have the same problem. No four hi, but have lo. I can hear the transfer case motor for just a split second and then...nothing. I am wondering if it may be a vacuum problem. I really don't want to have to replace the transfer case motor.

 

Both of you may want to check out THIS THREAD as it runs down the diagnostic chart for a No Mode Switch condition.