Whats up vette heads well just poped in the vette to take a spin in the 102 heat here to see how the ac would work as you can see its not an everyday driver. I havent had it on since last year and I know thats not good. But anyway push the button and nothing but hot air the fans didnt come on or nothing. I checked the two fuses in the panel and they were ok. I read something about a relay under the hood. Where is it? Any help would be appreciated.

 

I am not an air conditioner guru by any means. However, I have read pretty much every thread concerning AC problems for the past couple of months since mine doesn't work either. First, with the key on, but car off, push the up and down arrows for the temperature set at the same time and hold. You will see the display change to show codes. I forgot what normal was, I think it was 00. On mine when I do this, I get 00, then I can scroll and see every code that could possibly be generated. If you have a code, you can disconnect the battery to reset it. If it still doesn't work, then you need to see if the clutch is engaging. It is located in the center of the compressor (the large round thing that the pulley is on the front of). If the clutch is engaging, then you need to check your pressures. If it isn't, then you need to start troubleshooting the electrical.
At this point I will defer to those with more knowledge. If you can find a local service that will diagnose your system for cheap or free, that's what I would do. Then follow their recommendations as far as repairing and/or replacing whatever parts have failed. You can do a search of the archives here for more detailed information, however it is scattered across several different posts. Good luck.

 

A lot of problems are right in the buttons. Some say to take a pencil eraser and clean the contacts.

I have this happen inmy '93 on occasion, but usually only after the car has been running a while and is hot.

 

My AC head unit(push buttons) went on my 96. Felt like they were sticking or not making contact at all. Sometimes the fan would come on sometimes had heat and sometimes it even worked right. Easy fix. Check for codes though because the unit is a few bucks.

 

also there is a presssure switch in the system. if there is not sufficient pressure in the system it will not allow the clutch to engae. if the switch is bad it will not allow the clutch to work properly.

 

The pressure switch is located on the firewall on the passenger side, on the 3/4" aluminum line (suction). Chances are, your system is low on freon, because it leaks out of the compressor seals as they dry when you don't run the system. My '95 uses R-134a freon, which you can buy anywhere (I saw it at WalMart the other day for $6.88 a can). You'll need a fill kit, which comes with a hose and a gauge.

This next part is a big deal. When you put the freon in, make sure it goes in the low pressure side of the compressor, or suction side. There's two valve fittings on the passenger side of the engine compartment next to the wheel well. One is on a large (3/4") line (suction), the other is on a small (1/4") line (discharge). Do not EVER EVER EVER try to put freon into the smaller line. That line has sufficient pressure when the compressor is running to burst the freon can, and you can just imagine the possibilities.

Once you have it hooked up to the right line, note the ambient temperature, start the engine, turn the air conditioner on high, let it run a few minutes, then add the freon. Keep the can right side up, it'll get cold, and sometimes the valve even freezes, and you have to wait a few minutes before more gas will flow. The fill kit should have a chart that corresponds system pressure with ambient temperature. Another way to see if you have enough freon in it is to watch the condensation on the suction line. It's about right, on a hot day, if the condensation forms up to the accumulator (big aluminum cylinder in front of the engine).

My system had a leaking Shraeder valve in the suction line, so there are other possibilities for your problem. The valve is just like the ones in tire valves (probably better seals), but it takes a longer tool to get it out. You can check that valve by removing the black cap (if you have one, it unscrews), and wetting your fingertip and holding it over the valve. If the valve leaks, you'll know it from the pressure. I saw those on the rack at Autozone next to the freon.

If the problem persists, places like Autozone have cans of leak detector you can put in the system, and you'll need a UV light to see where the leak is. The system uses O-ring seals, so if you're feeling handy, it's not hard to change them. If you open the system, you'll need to pull a vacuum on it before refilling it, and that requires a vacuum pump. I found a vacuum generator that uses an orifice at Harbor Frieght Tools for about $17.00, but you need an air compressor to make it work. A regular motor driven vacuum pump will set you back $70-$100.00, but doing your own AC work once will pay for that.

 

Thanks guys for all your great knowledge Im gonna tackle it today.