Hi my 2003 blazer has push button 4 wheel. The other day i shifted into 4 lo and ever since then i cant get it to go back into 2 hi. When i try shifting on the fly nothing happens at all. Lights dont even flash on the button. When i shift trans into neutral and try to shift into 4 hi, the 4 hi and 4 lo button light up but then go right back to 2 hi.

Any guesses as to what could be wrong with my 4 wheel? I checked the fuses, they were good...

 

I am assuming that you have the 3-button switch in the dash (i.e. no Auto4wd button) which would mean you have the NV233 transfer case.

Check out this thread and see if it helps:
NV233 No Mode Switch (ie. 2HI to 4HI)

 

Ended up being my transfer case motor. At least they sell them aftermarket now. Half the cost that it could have been.