A/C not blowing cold air
 

My A/C was working fine one day, and the next day no cold air. The fan blows room temperature air. I checked the 7.5A fuse on the driver's side panel and the belts. No problems there. Is there anything else that I can check before taking the car to a mechanic? I do not have a pressure gauge.

Thanks,

Dan

Search for "temperature knob failure" It's a common problem.

There is a test you can do to verify that this is the same problem. If you test it and it shows good, then it could be an actual A/C failure. Those are more uncommon however.

Thank you for your reply, RIWWP. I found a diagnostic procedure written by Wingnut at https://www.rx8club.com/series-i-do-yourself-forum-73/diy-no-heat-repair-heater-control-158200/ . Is this the one that you were referring to? I ran the procedure and the display increments from 0 to 16 just fine.

I also found a procedure to reprogram the system that was written by Glyphon at https://www.rx8club.com/showthread.p...ntrol+knob+DIY . I ran that procedure and could not get the rear defroster LED to blink.

So does this mean that the control knob is good and something else is wrong such as the compressor went out? Thanks so much.

Yes, you have another issue, that isn't common. I'd recommend getting the compressor checked and validating that you have a full charge in the A/C lines as well.

Thanks, Just my luck that I have an uncommon problem. :o) I had to replace the steering rack a few months ago, and that was well over $2,000. I was hoping that the expensive repairs were done for a while. I will report back after I take the car to a shop and have the A/C system checked. Hopefully it just needs freon, but that seems unlikely since it was working fine one day and not working the next.

Just run over to autozone and get a can of refrigerant with a gauge attached to it. turn the ac on to full attach the gauge and get your measurements, this will only work on the low side (cap with a large L on it). If the gauge is in the green zone you have a full charge, if it is slightly low you can top it off. check it about 2 weeks later if its slightly low again you can shoot some uv dye in there and run the system till you find the leak.

if its completely flat you'll need to replace the component that failed. Most likely the condenser, at this time since the systems flat you can also replace all the o rings as well.

This happened to me too....checked everything and when all was said and done, it was a blown condenser. Sits so low to the ground that 2 rocks managed to puncture holes trough it. Hope this isn't whats up with yours...shits expensive...270 bucks for a new one!

I got a used one for $50 shipped on ebay.

Thanks for the advice, Shadycrew. I went to an auto parts store and they tested it for me. The gauge was in the yellow zone close to the red, and the attendant said that meant there was air in the system. He suggested that I vacuum the system and recharge it. Does this sound right?

Thank you.

Very unlikely you have air in the system, that would give a false 'high' pressure reading.

The yellow zone indicates compressor suction pressure is low. Low pressure there will stop the compressor working, there's a pressure switch.

You need a pound of R134a, either from a can or from an aircon place. Don't go to a Mazda dealer, they aren't aircon specialists, at best they'll just replace the pressure switch or something.....go to an a/c place that will top it off.

huh? air in the system?

If your charge is low you have a leak somewhere...

You can try recharging the system and see how long it holds, there is a chance you just have a busted o ring causing a super slow leak. Your best bet is to get some UV dye and throw it int he system and see where your leak is coming from.

Ok, I am just going to throw a $20 can of R134a in and see what happens. I bought a can with a gauge. I take it you don't advise vacuuming the system before adding more R134a? Just add more?

I don't have the equipment required to see the UV dye once it is in the system. Don't I need a special light and glasses to see the leak?

My car is 8 years old and I have never had problems with the A/C before. Is it possible that enough refrigerant leaked out over the last 8 years causing the system not to blow cold air? I can hear the compressor clutch engaging and disengaging when I turn the AC switch on and off.

Thanks a lot.

Retrieving the refrigerant is always a good idea but the equipment needed for that is stupid expensive.

our systems are so small that they don't really lose charge gradually. unless its something very small like an o ring. you can get the UV test kit at autozone that comes with glasses the dye and a light. not sure if it comes with an injection device.

In any event yes I would just top off the system and test it again in a few weeks. There's some really great DIY's on YouTube that you should watch. Everyone has their own methodology behind Automotive HVAC. But I think it would be good for you to watch the DIY's to get a feel for the system and how to charge the system.

This guy is a giant dork but its a good video to start off with.
Where are you at in Texas?

Thank you all so much for the advice, and especially for the YouTube video. It was very helpful. I followed the directions in the video, which matched the directions on the freon can. The attendant at the auto parts store did not measure the pressure correctly because he did not ask me to start the car and turn the A/C on. That's why he measured a slightly high pressure. I measured the pressure with car running and the A/C on max. The reading was in the green part of the gauge indicating low pressure. I added freon until it got to the blue section and my A/C works again. I will check it again in two weeks to see if it is holding the pressure. If not, I will buy the UV test kit.

On a side note, my A/C has never worked very well when the car is idling such as at a traffic light. It gets cold when the car is moving. Does this have to do with the hjgher revolutions on the compressor when the car is moving? Is this normal for RX8s or is something wrong with my system?

I live near Austin and just noticed that you are from Austin as well.

Thank you all very much!

Excellent glad you got that squared away!

The AC not being very cold issue is quite common for our cars. There's some cheap fixes for it and if I'm not mistaken there is a DIY on it. You can wrap the line that runs behind the engine with some heat resistant foil or something like that.