Left Turn Signal Failure

[swick20]

Alright, so I have had some serious electrical issues for a couple months and thought it had finally been resolved. My truck started to loose all electrical power for a split second but would come right back on w/o killing power to the engine. This seemed to only happen when I would be turning sharply at slow speeds. Dealership said it was a loose ground. A little bit later down the road, same problems but getting worse. Truck would actually die now. Took it back, more ground wires they said. 3 days later, cruising on the interstate, hit my turn signal to pass a car and power flashed. Didn’t die but did this a couple more times. Then getting closer to my destination, I turn my signal on while breaking and it automatically put me back in cruise control at 80mph!!!!! Take it back to the dealership, they keep it for a couple days trying to get it to do the same thing so they can start reading codes. Finally, they get it to shut down. They changed the fuse box and said my negative battery cables was weak. Haven’t had it shut down on me yet , but, my newest problem is the left turn failure indicator comes and my whole left side headlight assy is extremely dim. Any thoughts would be appreciated!!! 2015 Silverado 1500 LTZ 6.2