not sure on gm trucks but im sure the hookup is pretty much the same. i had a phantom autometer tach in one of my other cars but black was ground, red was constant power, yellow was acc, and blue with the white stripe was to my rpm out wire from the cluster. i also had to solder blue to the actual board on my cluster. good luck man.
A forum community dedicated to GMC and Chevy full size owners and enthusiasts. Come join the discussion about Silverados, Sierras, and other full size trucks performance, modifications, suspension, lift kits, tires, maintenance, and more!