Head Unit Wiring Diagram for 2018 Chevrolet Spark LS?

I’m attempting to install rear speakers in my 2018 Chevy Spark LS, we got the amp installed along with tapping into the front speakers and have the ground and power hooked up but something is not working right..either my car will play music for a good 30 seconds and then cut out completely or it won’t play music at all and just make a constant buzz from the 2 front speakers. I figured if I could get the color codes for the wiring and/or pin-out for my vehicle then we can just directly connect to the head unit. Any advice? Tips?Cmorg

Radio 12V      Red/Green      +      Radio, green 16 pin plug, pin 8 or brown 20 pin plug, pin 20            Radio Ground      Black      -      Radio, green 16 pin plug, pin 16 or brown 20 pin plug, pin 10            Radio Ignition      Violet (retained accessory)      +      Cigarette Lighter, 3 pin plug, pin A            Left Front Speaker (+/-)      Blue - Brown/Blue      +,-      Radio, green 16 pin plug, pins 1 - 9 or brown 20 pin plug, pins 18 - 17            Right Front Speaker (+/-)      Yellow - Yellow/Black      +,-      Radio, green 16 pin plug, pins 2 - 10 or brown 20 pin plug, pins 16 - 15            Left Rear Speaker (+/-)      Green - Green/Black      +,-      Radio, green 16 pin plug, pins 3 - 11 or brown 20 pin plug, pins 13 - 14            Right Rear Speaker (+/-)      White - Blue/Black      +,-      Radio, green 16 pin plug, pins 4 - 12 or brown 20 pin plug, pins 11 - 12            Aux. Audio Input Left (+/-)      Gray - Violet      +,-      Radio, gray 20 pin plug, pins 9 - 8 or 19 - 18            Aux. Audio Input Right (+/-)      Green - Violet      +,-      Radio, gray 20 pin plug, pins 10 - 8 or 20 - 18            Rearview Camera Video      Gray/Yellow - White/Blue      +,-      Radio, gray 20 pin plug, pins 15 - 14