Teddyshrew

My 2011 Sierra 1500 similar problems. I have a new battery. My door clicker stopped working had got it to work for short time then quit working all together. My battery gauge on dash reads 15 V most all the time. It will drain the battery it it sets for 3-4 days. The park lights sometimes come on in middle of the night or will stay on. Head lights ( switch on auto setting ) will flash. I gust purchase this unit a few months ago. If setting at store with it off and in a few minutes it dash comes on and says low battery voltage. Dealership can't help they say voltage is normal and can't find anything wrong with loss of batty voltage???? . My email is [email protected] Any advice as to what I can do myself repair shops here are no help