A/C Won't blow properly or cold

[BrandonC300]

Hello,

I'm not too educated on cars, but i'm trying to learn. I own a 1989 Nissan 300zx 6 cylinder non-turbo. I haven't had the car for very long. It has a couple issues, but one i'm trying to deal with right now is the A/C. It only blows extremely hot air, and through the defrosters, as well as the left and right dashboard vents. It worked fine when I test drove it. Then the mechanic messed around with the headlight/blinker switch. As well as adjusting th left headlight right in front of the compressor. I've tried to convert to R-134a and recharge to at least make it cold, but that did no good. The compressor kicks on when I turn on the A/C still as well. I'm lost and my mechanic lives too far away for me to have time to get there.

[evildky]

Very common issue on these cars, the heat c*** is controlled by vacuum as well as the flapper doors in the dash, first and foremost check the vac lines, they are small and get brittle and break, could be as simple as replacing some bad vac lines. There are vac operated dashpots under the dash, above the trans tunnel near the drivers right foot, these dashpots can stick or crack and need replacing.

some additional detail can be found here
http://www.xenonzcar.com/z31/hotairfromac.html

[Desert Rat]

Yep, start chasing vacuum lines. I had one come un done behind the glove box that caused your symtoms a while back when I had my Z31. Those lines do get brittle and often snap when youre working with them. There are several more HVAC vacuum lines under hood - 3 of which go to the vacuum canister behind the right headlight. Get new line and start replacing methodically, paying attention to how things come apart.