1985 300zx and it only blows out hot air when i turn the a/c on. What can be the problem!!

have a 1985 300zx and it only blows out hot air when i turn the a/c on what can be the problem!!”

Well, obviously you have an AC problem. The first thing to check is the refrigerant level. Hook up a set of AC gauges and see what the pressure is. If it’s low or empty, then evacuate the system and fill it up with refrigerant. Then look for a leak and if you can’t find one, see how long it blows cool and live with it if it lasts for months at a time. On the other hand, if it’s full of refrigerant, then you probably have an electrical problem, or a blown AC compressor. Hot wire the power to the AC compressor to see if it comes on. If it does and then blows cold, then you’ve got to find the electrical short in the system. If the compressor won’t come on even if you hot wire it, then the compressor is shot and needs replacing. Now realize that even though that car is pretty old, it still has a rather complex Nissan computer controlled AC system that can be a Stinker to diagnose IF you have an electrical problem in the AC system.