Idk if this solution is known already but for me the easiest way i added power behind my dash is I bought a “12V power adapter cigar lighter ignition socket” on eBay and a usb port with the negative and positive cables,you just put those 2 together and it’s simple as plugging it in, red with red and black with black, no need to modify ur own cables,has been a month and no issues so far (2019 Silverado 1500 high country)