Got a 97 Blazer LS 2WD...
Last couple of days my ABS light on the dash has stayed on constantly, finally got my scan tool out today and checked codes...

No ECU codes? It didn't find any codes.

What would cause my light to be on on the dash, and no trouble codes in the ECU? Seems to be driving fine, no brake issues except the night before last coming home from work the ABS kicked in one time on normal braking with (what I felt) no loss of traction... Other than that, nothing, driving to work and back the last two days, errands, no problems...

 

The ABS codes are not stored in the PCM. You need to get a scanner that can read the ABS codes.

 

pop your front wheels off and look at the abs wires. Are they in good condition? Did they rub against the rotor or caliper and get chewed up? Easiest/cheapest way that I know of to find out why the light would just "pop" on like that. Of course, having a brake scanner is just as handy as having a code reader. If you have neither then you should definitely pick them up at your local autozone/advance auto.

 

You can test the output from the front wheel speed sensors using the information found in the thread linked to below:
Brakes - Low Speed (below 5 MPH) ABS Activation

 

I'll have to check that out this weekend, if I'm not working OT...

Didn't realize I needed a different scanner for ABS codes, I'll have to check one out, thanks!

 

I would pull the codes first.