I have searched the forum and found questions but no answers. My abs/brake light in my dash just started to come on today. I cannot notice any difference in the braking but I did get some mud in the wheels and washed it out. Then drove 200 miles, parked, then about an hour later drove to the store to have the lights come on. What gives? Its a 2001 Chevy Silverado 1500 HD.

 

pull the wheels and clean the sensors and also do the easy solution and check your brake fluid, if the level is low the light will come on too.

 

Yeah that sounds like the wheel speed sensor. I think they are just on the front wheels. It could be from mud getting in there, or a bad wheel bearing. I've never pulled them apart but you can ask around and get some help on here with that. If that doesnt work, shoot me a message, I've dealt with a lot of hell working on my ABS trying to chase down a problem that turned out to be mostly unrelated to the ABS malfuctioning.

Good luck!