Blue_SS

I will hazard a guess that your wheel speed sensor has water intrusion. There is a 2-tier warning system. The ABS light is the first level, and the brake light is the second. Red is supposed to get your attention more. Moisture levels or other slight movements can make the connection strength change. Resistance levels going up and down makes the ABS module grumpy.

Just replace what you were going to replace, and see how it goes.