So I have a 2015 Tahoe ltz 4x4 with about 143000 miles. I notice that when my voltage goes down my right turn signal blinks like it won’t recognize the Cadillac lights I installed. I also have a rear view camera problem when I put it in reverse it’s like it’s dark and u can’t really see it or it says service. Also my blind spot on my left side illuminates without a vehicle nearby sometimes. When I turn my fogs on u can see them dimming with the rest of the lights that are on. The dealership said my battery is fine but my friend hooked it up before hand and said the cold cranking amps go way down after starting it. Truck sounds like it’s weak kind of. Like a 2008 pontiac. Sounds like something is dieing. I just know that something isn’t getting enough power. I will say one time it died while backing up in driveway. Has never done it since. Please help.