I have the factory service manual for my 1977 and it is the only place to get accurate vacuum hose and wiring schematics for AC and turn signal issues. The AC system uses a complicated system of opening and closing vacuum doors and tripping switches to work correctly. If your system isn't blowing cold air anywhere, it's probably not the vacuum hoses inside the car. Freon leaks are by far the most common problem. Also, make sure your compressor is engaging when turning the ac on. Get the manuals. You'll be glad you did.