trac off/abs light come one sparatically

I am new to this website and I have an 1999 Oldsmobile Alero GL 3.4L V6 Coupe. I love this car to death, but recently have had problems with the ABS and Trac Off lights coming off and on. They always come turn on simultaneously; however, they come on at different times. A lot of the time, the lights appear whenever I turn on the car, but sometimes, they will not be on when I start the car and come on a little later. Also, the Low Trac light comes on from time to time for only a few seconds. I went down to the local GM dealership and they said it would be 73 dollars to even look at the car. I dont want to waste that money if it is possible to fix it myself/ easy for mechanic to fix if I know what is wrong. I have read through a few of the other discussions and most of which blamed similar problems on the wheel sensors. I want to know if this is probably the case and if it will fix the problem if they are replaced. Also, what should I specefically tell the mechanic whenever I tell him what is wrong?

Please help me, Chris.

There is a high probability you have one or more bad wheel sensors. Best thing to do is to take it to a mechanic that has a scanner capable of generating chassis/ABS error codes. If a wheel sensor is bad the whole hub assembly will need to be replaced.

Also check to make sure it is not a wiring issue. Check the electrical connector at the hub. The wiring to each sensor routes along the lower control arm of each wheel.