I have 2007 envoy Denali with air conditioning issues. When u start the engine and the alternator will charge at 14.5 and after it has ran 15 minutes or so the charging system will drop off to 13 the air conditioner pump will kick out. It will not kick back in until it goes above 14 again. Have had 3 different batteries and 2 alternator. I have had the Freon checked and it was 1/2# low but still does the same thing. Dealership doesn't know what to do. If we pull our camper and turn some of the interior lights on it will stay charging at 14 and will keep the air going. Someone mentioned that there is energy saving mode that saves fuel by not charging as high when you are driving. Don't know what to try.
