Autozone or eBay would be a good start.
Order a Helms manual from Helmsinc.com
This is the official GM/cheverolet repair manuals. I own one with wiring diagrams. Well worth the money, or you can get a used one off eBay.
You can find a 1999 Chevrolet Corvette radio wiring diagram in a Corvette service manual. The service manual can be found at your local library. Most Chevrolet dealerships will provide the radio wiring diagram free.
Most Chevrolet dealers will give you a free 1980 Chevy Corvette wiring diagram. The wiring diagram can be found in Chevrolet service manuals at your local library.
Try PAINLESSWIRING.COM. They will help you with the wiring if you have any problem.
Library will have older year Chilton's manuals, they have wiring diagrams
Diagrams should be used as guides when making changes to a car. The wiring diagram for the 1978 Chevrolet Corvette can be found in its maintenance and repair manuals.
Lectriclimited.com
Try the shop manuals at the local public library if you have one. I have found them to be a great source of information. [the library i mean]
You can find a wiring diagram for your 1984 Nissan at most Nissan dealerships. The wiring diagram is in Nissan service manuals. The service manuals can be found at most local libraries.
A person can find a wiring diagram for a 1984 Mazda b2000 in its maintenance book. They can also ask for a print out at an auto part store.
wiring diagrams are in a repair manual or you could go to corvetteforum.com and someone will help you
The 1978 Corvette power window diagram can be found in the cars maintenance and repair manual. A person can get these manuals at an auto part store.
Try looking in a motor manual at your local library.