I have a 92 s10 Blazer. This past winter I found out that my high 4 wheel drive is went out, it will still go into low though. It has an electical switch so I thought maybe that went out but I do not understand why it will still go into LOW. Any thoughts?

 

It may be a problem with the encoder motor itself not properly sensing the position of the shift sector shaft for 4HI. If this problem were to occur, it would revert back to 2HI.

Check out the thread below as well as a few other 4wd related threads in the Tech Article (DIY) section (index link can be found in my signature below):
NV233 transfer case / encoding motor switch

 

the 2nd gen has a switch on the transfer case. a little 3 prong thing that is open for 4 low and closed for 4 high. My 4 high didn't work, because the switch stayed open. I replaced the 20$ switch in 20 min, and my 4x4 worked again in high and low. I'd check into that.