I had a complete brake job done on my 2006 Colorado & afterwards the ABS light was one steady. Took it back to the brake shop & was told that my wheel bearings were bad. This light had NEVER been on before the brake work was performed. I am having NO noise from my front wheels that make me believe this. Got a second opinion and they said my wheel bearings are ok and that it is just my wheel sensor that needs to be replaced on the left front. NOW I am really confused.!! Who to believe.?? Light comes & goes. Now at low speed I apply the brake pedal & get a hard grinding sound & a sound of a pump whining (this does not happen all the time)? I have talked to a Chevrolet dealership & described the issue & they tell me that sensor can be damaged when brake jobs are done. I can not get the truck to duplicate the problem when a mechanic is present. I am now planning to just wait till something breaks & then I will know for sure what the problem really is.