My 2004 Blazer started acting up today, may simply be cold weather but want any advice offered. We have had a fair amount of bad weather and I must run 4x4 HI to get in and out as of late. I left the truck in 4HI last night, left today and when I got to the main road it would not change out of 4HI to 2HI. I drove a short ways until I turned off road to a safe area and kicked the buttons on and off a few times. I forgot i should NOT have done this but also hit the 4LO button in park. Not sure that really did anything but after a couple of minutes the 4HI and 4LO buttons flashed a few times and it went in 2HI. Now I can't get it back into 4HI.... I can get it to 4LO OK when in neutral, as it should be but it refuses to go into 4HI from 4LO although it does try. When I put it back to 2HI it won't make a noise when I hit 4HI... It has been below freezing here now for 3-4 days...maybe it is stuck??? I am digging through manuals, but so far nothing that will help me.