The wifes Brake and ABS light came on the other day and I tried to pull the codes with my Genisys and couldn't get a code.(That's in another thread). 98 MALIBU LS

Here's the problem I jacked up the car and I'm getting good brakes at the front, but nothing at all in the rear brakes. Fluid level is good,pads and shoes only 3 months old.

Could this be the ABS motor pack?
If so can someone tell my where this is located. I think it's under the battery that's where I see the brake lines, but I'm not possitive that's it.

This car has been nothing but problems in the last 3yrs. Water pump, ABS sensors, broken springs, muffler.

Any help with this would be appreciated.

Thanks
Pete