2004 Blazer 4x4 Issues

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.

What transfer case?
Does it have the auto 4W button or reg 4W?
Any check engine or transmission or transfer 4W lights on?
How many miles?
Transfer case been serviced.
How is fluid and fluid level?

Has the regualar 3 button set up ( not automatic TC). Sad to say I do not know when it was last serviced. Bought it recently, was a government vehicle that was maintained pretty well from the records I see, but they are not in detail. It has 85,000 miles on it. I have not checked the fluid level in TC as the weather is just nasty. Will take it later todayto a local place I deal with and check it there.

Not sure what TC is in it, no lights anywhere.

Has the regualar 3 button set up ( not automatic TC). Sad to say I do not know when it was last serviced. Bought it recently, was a government vehicle that was maintained pretty well from the records I see, but they are not in detail. It has 85,000 miles on it. I have not checked the fluid level in TC as the weather is just nasty. Will take it later todayto a local place I deal with and check it there.

On that one you ground pin 13 on diagnostic connector and read codes from shift button lights.
Post back any codes.
This link has some info on that one.
http://www.automotiveforums.com/vbulletin/showthread.php?t=572914

I will see about the codes....I assume you mean the main computer port. Would Advance parts have a scanner normally for this I wonder? Also, what do I look for, flashes, numbers or what if I short out the pin? lastly, the TC is fine as far as fluid level and color is conerned.
I just got back with it and tried to switch a few times while out. I can switch still into 4LO and 2HI with no problems but noticed once that when I took off in 2HI it seemed to be holding back, like it was still in either 4HI or LO. I got a loud pop on the right side front area and it then ran fine. I remember this happened once before on me a while back, if that sheds any light. I actually got it into 4HI (according to the panel) by trying to get it into 4LO. But it was not fully engaged so I did not run it. Barring any codeswe have had a lot of freezing rain, snow, and ice here...maybe since it is still below freezing something is sticking.

Look for flash codes 1 -4.
Post back codes.
It take a transfer case capable scanner to read codes.
Advance an AZ usually do not have them.

OK, all buttons flashed two times, so i assume it is a DTC002 code based on my book. It mentions the encoder motor and a series of tests. Does thsi sound right and what would you guess based on my troubles so far?

Yes.
If it is a flash flash and pause and then flash flash it is code 2.
But a flash then pause and flash it is code 1 repeating itself.

Code 2 is encoder motor or circuits.
If you have the book check the circuits and if they are OK replace encoder motor.
Also clear code and see if it returns.
Sometimes a battery disconnect will bring it back on line.
Good Luck

Thanks, was wondering if clearing it out would help. Will unplug the fuse for the unit and see if it comes back on line. Considering the ice and freezing rain it saw maybe something caused it to throw a false code. Will advise.

Sometimes.
But give it a try.
Let us know how it goes.

Well I unplugged the fuse as the manual says and then cycled the ignition switch, but it still does the same exact thing. Not sure if the code is clearing...weather is not going to permit me to deal with it much today but will advise later what I find.

After you clear codes always recheck for codes.
If same code comes back go threw the repair chart for that code.
a alldata online sub or a factory repair manual have the repair info and flow charts and test to run to find the problem.
http://www.alldata.com/products/diy/index.html

Sorry I never got back to you folks sooner, forgot to tell you the truth...anyway I eventually unhooked the battery and it did come back online. I suppose when we left it in 4hi all night and being cold it just could not do anything due to being froze. So far I have not had any further issues with it.