I have a 2007 half ton 4 door GMC Sierra. My battery goes dead if the vehicle is not driven within a few days. I have tested the battery and the tester says its good and also the altenator I tested and it says that its charging properly. My brother has a 2009 GMC Sierra Denali pickup and also a 2006 Escalade that both go dead if they are not driven with a relatively short period also. Dealership said that it could be the onstar or the computer but I don't know if I buy that. I am worried because I will be going on a trip and my pickup will be parked at the airport for 10 days and I know that it could be dead when I get back. Any suggestions because this new of vehicle shouldn't be having this problem, plus my brothers do it too.