abs brake light indicator - failure?

95 Rodeo, had only rear abs.

For a few years now I've had the abs lamp on, but intermittently. Does this mean the ABS is failing, and only when the light is on, or is it just a code issue that needs to be properly reset? I have never done anything to fix it of course, but wondering why it is so intermittent. I'd be driving along not even hitting the brakes and the light would go off, randomly. It passes inspection just fine and have never had a brake issue otherwise.

Its most likely there is crap on one of your wheel speed sensors. I'm not as familiar with the '95 rodeos...but read the Isuzu FAQ, and do a search (i'm not trying to be ass)...somewhere in those threads are instructions for doing a self test I think which tells you which sensor is crapping out. You can try cleaning the sensor (its magnetic, and brake dust or metal flakes could be on it...giving it an invalid reading) or replace one. With the abs out, you still have standard braking, so of course you should pass inspection.

Check/clean the wiring connections. The abs sensor is on the top of the rear differential. I get an intermittent light and have changed the sensor and cleaned all of the connections, but still get it here and there.