ABS light won't go off recently had both front wheel bearings replaced on a 1999 gmc jimmy - the ABS light came on immediately during a test run, i told the mechanic about it and i was told it would reset itself after i drove it a while, it's been two days and the light has not gone off...what is the problem

There are ABS wheel speed sensors on the front wheels behind the hubs. It is possible if the hub where replaced either the pick up ring mounted to the hub itself was not installed or might have purchase non abs hubs or they just did not switch the wheel speed pickup ring on the new hub. Another thing could be either the wheel speed sensors are mis adjusted or when they replaced the hubs they hung the spindle by the abs wire and either pulled it out of socket or messed up the wires internally. Here is a basic abs system http://www.ehow.com/how_8511860_diagnose-abs-brakes.html if you have any other questions please let me know. Also please leave good feedback.

The ABS light doesn't come on because u need a brake job, it comes on when it senses a failed part like a wheel speed sensor, in order to determine exactly what part is keeping the light on and disabling the Antilock Brakes you will need a shop to scan the systems comuter for fault codes