abs and brake light on

You need a mechanic. When the warning light has turned on, a diagnostic fault code has been stored in the ABS Computer. That code will lead to the circuit or system that requires further diagnosis.

The most common cause on your car is a front wheel bearing. General Motors loves to design cars with very expensive assemblies. That saves them time and money on the assembly line but often makes repair parts for their cars very expensive. The front wheel bearings develop a little looseness, which is common and normal, but since they build the wheel speed sensors into the bearing as an assembly, that looseness allows the speed signal to drop out and make it look like that wheel has locked up. Since this happens when you are not pressing the brake pedal, the computer knows the wheel has not really locked up and that missing signal is a problem, hence the warning light.

That bearing wear often causes a problem in as little as 15,000 miles. The dealers' scrap metal bins are full of old bearing assemblies. There are other possible causes for the warning light being on, and that's why having the code read is the place to start. Be aware too that some ABS Computers can only store one code at a time and some computers will not test other things while driving when something it compares it to has a code already set in memory. That means your mechanic might read the one stored code, give you an estimate for repair, perform the repair, THEN a different problem will be detected and set in memory and you have to start all over again. That can result in a lot of frustration, the assumption the mechanic didn't fix it right the first time, the assumption the mechanic doesn't know what he's doing, or the assumption he's trying to rip you off. In reality, he is just as frustrated as you are. The chance of that happening is very small if you take the car in for service right away before any second problem has chance to occur. People run into this more often when they wait months or years to get the problem fixed. That gives a lot of time for a different problem to pop up.

cardiodoc, they can have it scanned and do most of the work themselves and save a pretty penny in labor. They'll just have to take components to a good machine shop to have the bearings pressed in and out.

Taking it to a mechanic is easier, and doesn't get you all dirty and greasy, with bloody knuckles, but you'll save several hundred dollars in the process.

cardiodoc is exactly correct about the frustration level with a fault like this. Doing the work yourself gets rid of the "he's trying to rip me off" frustration and the frustration of paying an arm and a leg for labor. And the recurring "Now we found this problem" phone calls from the shop.

True on both accounts, but with the Mitchell1 subscription, all the information needed to test the systems is there. The scantool can usually be rented or borrowed. And, if need be, here's a relatively inexpensive scantool from Amazon:
http://www.amazon.com/Autel-MaxiScan-MS409-OBD-II-Scanner/dp/B001LHW9YG/ref=pd_sbs_auto_7

I don't like telling people to take their cars to a mechanic, unless it's something really deep and troubling. Most everything the average person that knows how to read can do, with the right help and the right tools. We're the right help part. Most parts stores can help supply the right tools, either rented or borrowed/loaned.