Yesterday my 99 blazer i need to go up a small step hill. I put it in 4 lo which was odd because it hasn't worked in a year, but auto 4wd and hi 4 works. Well when I did that it is now stuck in 4 lo and it will not shift in into high gear. I wanna say it goes to first to second but that is it. The fastest I can go is 50mph but at 4000 rpm. I have unplugged the battery to zero everything out and let it sit over night unplugged. Plugged it back this morning, same thing. I push all the other buttons and it will flash but then nothing. I do hear an odd click behind the dash too when i do this. What is up? This is my only vechile and I need it on the road soon!

 

Problem fixed! Put in Neutral tried to change from 4lo to 2hi, worked. It shift into it hard though. From now on, 4hi or 4 auto for me.