Like_A_Rock_Bottom

Hi, everyone. Sorry to revive an old thread, but I recently got a 2014(.5) Silverado that has a vinegar-y smelling a/c when first starting to blow. I read that it's most likely mildew. I tried one method of running the air on maximum heat for a while to see if that would "cook" the mildew before trying other methods. This did not work. Where exactly would I find the drain line in this truck? I've not found a good source on youtube for this particular model year range of GM trucks. Any help would be appreciated. Thanks! Great forum, btw! Been checking out a few threads on various topics, but decided to sign up.