Brake Abs Warning Light problems of the 2007 Chevrolet Uplander

Incident 1: tracking pin on driver's side rear sliding door broke, not allowing door to close, had to pull fuses and manually shut, if tried to open now, door falls off track, unsafe. Taking it to the dealership made it worse, no resolution from Chevrolet company. Incident 2: service abs light comes on, brakes pulse, when engaged will not disengage when brakes are released without a waiting period, does not always engage immediately making it difficult to come to a complete stop in a timely and safe manner. Technician could not find issue when I took it in to be tested. (intermittent dash light not showing up when I take it in).

Approx. May, 2009 while traveling, I applied the brake on my Uplander and the abs light went on. It would not go out unless the vehicle was shut down. The brake feel was hard at first and then it slipped as if I was traveling on snow to keep the wheels from locking. The pavement was dry. This was the first time that this has occurred and I have had it back to the dealer 3 other times since, but they cannot find or fix the problem. I feel that this is a safety issue that gm should address. The current mileage is 77000.