The best place to find your specific vehicle's chassis and engine wiring diagrams are in automotive repair manuals made by the Hanes or Chilton companies. These manuals are available at your local parts store.
There are several online sources for wiring diagrams which you can find with a simple search. However, you're better off with a Haynes or Chilton manual.
Well typically one can be found by searching online or looking in forums. However you can purchase a repair manual and it should include all the diagrams you would need.
