I get almost all of my wire from the vehicles in pick-a-part yards. Particularly the Dodge trucks from the 80s. They used much of the same size and colors of wire that our muscle cars did and they are still finding their way into those yards. Other than those trucks, the biggest issue with the wiring in newer vehicles is that a lot of it is smaller than our old wiring. But with the huge selection there, almost anything can be found.