After explaining to service rep that the vehicle would often not start & that service engine light & security light were on he suggested a dianostics test. They had the vehicle for 15 days & said the 2 month old battery was bad. So I installed another new battery. But the problem got worse. We received a phone call from dealership asking how we felt about the service. I told them that the vehicle was not fixed. The lady on the phone said she would make sure something would be done.(smoke screen)But we never heard back from them. We decided to bring the vehicle back again. After explaining the problems again to a different service rep they tested it again. This time they found 7 different codes but still blamed the battery. I told the service rep that I had just put in a second new battery & that the odds of two in a row being faulty was rediculas . The mechanic told him that the battery terminals were not tightened properly. I am a mechanic too, so I know how to install a simple battery & I also know that they were cleaned & tightened properly! My wife & I decided to trade in for a newer car. Then the service rep told me it would cost $2700.00 to fix the vehicle & they would only give us $500.00 for a trade in. The vehicle is a 2001 Bravada fully loaded & in good condition. I refused to pay for second test having felt that they did not do it right the first time! So they charged me $43.74 to tighten two battery terminals that I know were tight! I own a 85 corvette, 87 S10, 94 Silverado, 99Silverado, 05 Silverado & a 07 Impala SS. All of which I trust & love. I still believe GM is #1, but will not go to that dealership ever again!