So, 2001 Blazer 4wd.
NOTE: I have not taken it in to get an OBC reading.
ABS light: ABS started to "malfunction" when turning sharp around a corner and breaking the ABS would engage especially if there was a bump as well. Now ABS light stays on and the ABS does not work. Used to have the break light warning light to on also, but not now. Will an ABS problem register on an OBD reading?

4wd question: 4 button display with AUTO 4wd. Put it in 4 HI or AUTO 4wd it does engage but the light continues to blink in either selection.

 

If you can get the codes read for the 4wd it will help your diagnostic, If you cant, check the vacuum system for the 4wd , check and clean the TCCM connection ....Do you hear the TCCM clicking and do you hear the encoder motor moving ?.

 

Vacuum system works fine because, as stated, 4wd engages. Guess I will look at the TCCM.
Thanks

 

Are you sure it is engaging ? , The flashing lights are usually a sign that it is not ....and if you have a bad TCCM or encoder it is doubtful that the system is working properly.