Blazer brake light is on

Okay, the brake light went on on the dashboard, but I feel no notieceable change in the braking.

Of course the manual givea a lot of help on this, stop the car and have it toed is what it says.

Now all brakes were redone 11K ago, although the blazer has 197 K on it, so one brake could be dragging and wear down a pad. but, that should not warrant the light going on..topped off the reservoir with fluid, and that is okay.
No apparent leakage anywhere, pedal has not softened.

I have power booster fail on me, (on my way to mid ohio pulling my race car..
nothing like driving 300 miles plus with just about non-existent brakes)...
and that never turned the light on.


any ideas.. with 197K, I want to stay away from major repairs.

thank you


r

What year?
2W or 4W abs brakes?
Red or yellow brake kight?
Have you checked for abs codes?
MT