I have a 94 S10 Blazer four wheel drive push button.My vehicle will not come out of 4hi or 4low.When I push the button for it to go out of 4hi or 4low I hear noise somewhere but it does not come out.Do you know the problem is?

I had this on my 2002 blazer (4wd 4dr 6cyl) about a year and a half ago. I found two things out. First, have to try shifting out of 4lo while in neutral with foot on the break. It seemed to work better while on a small incline (like waiting to put the boat into the water, not on the ramp but the somewhere shortly before ramp).
I finally decided to try to replace the neutral safety switch after much reading online. It worked and has worked perfectly since then. The shops I took it to told me to put in a whole new motor for about $600. I think I got the safety neutral switch for about 50ish. I have a pit in the garage so it was pretty easy to get under the truck to the transmission and remove the existing switch board. I then just attached the new one and plugged 'er in.
Hope it helps, good luck.