Need some help. I might go look at a 84' 300SD with 190,000 miles on it. But the a/c does not work. Are there any tips that I can use to figure out what is wrong with it when I go to look at it. As far as if I can troubleshoot if it's the compressor and so on. Thanks for any help.

If you can't find what is the problem you take your car to the mechanics..he will tell you whats the problem..If your a/c is not working check for the a/c gas..the gas might be empty so it is not working..