Problems with 2005 Buick Rendezvous SERVICE BRAKES, HYDRAULIC

I own a 2005 buick rendezvous that is having safety issues concerning the awd brake system. four times over the last 5 years the awd and anti-lock brake system have stopped working. the latest time was today 3/8/11 when the brake system failed again and the i was barely able to stop the car before it entered a busy highway. after researching the internet it seems that numerous other people have encountered the same issues. i have had the problem repaired three other times. the wheel speed sensor and the hub have been replaced and the wiring harness repaired. *tr

Dt*: the contact stated that the vehicle's abs system failed on 07/15/06 resulting in a collision. the vehicle was traveling at 25 mph when traffic forced emergency braking causing the vehicle to nose dive but continued to roll forward. the wheels did not lock up and the abs system did not engage. there was no warning prior to the failure which occurred on dry and flat road conditions. the contact expressed that during the incident it felt as if the hydraulic brakes were not grabbing, and conceived that the vehicle brake failure may be due fading caused by heat. the vehicle is equipped with 4-wheel antilock and 4 wheel disc brakes. the manufacturer was contacted on 07/17/06 who determined that the vehicle needed to be inspected by a technician and could only be scheduled for a later date. the contact performed three brake distance tests at the residence which resulted in three different braking distances. the contact heard one wheel chirp, and felt a pulsation in the pedal during the first test, but no pulsation was felt during the other two. the last test resulted in the vehicle stopping a longer distance than both the first and second tests.

Dt*: the contact stated while driving 35 mph on normal road conditions the lights for the awd and abs systems illuminated. according to the owner's manual when abs illuminates the vehicle should be stopped and towed for assistance. this incident has occurred several times and the dealer advised the contact to drive the vehicle eventhough the manual recommended towing. the contact was not aware of the remedy repair to fix awd and abs illumination problem.