First off, no HVAC codes. I had the system evacuated, leak tested and re-filled a few weeks ago.

Most of the time when I press the A/C button, the light will flash a few times but no A/C. Sometimes the A/C will come on if it's set to auto, but most of the time it won't. Even turning the temp down to 60 still won't get the A/C to engage, although the fan will certainly max out.

Any ideas?

 

Does the compressor clutch even try to engage? See if you can check the harness at the compressor for voltage.

If it does, it could be as simple as a low-pressure (or even the high side) switch that is bad.

Ensure you have the correct system pressure-charge. The system will default "off" if it is not.

 

I can go back by the A/C shop Wednesday AM to have them check the pressures. The thing is, it works SOMETIMES. I hate these intermittent problems.

 

Keep us posted.

 

I would think that if its right at the pressure threshold that it could cause it to work sometimes and not others. A pressure switch could also be going out.

 

If it was not properly evacuated when fixed, moisture in the system will cause issues with pressure swings with temp changes.

 

Auto mode: If the outside temp is below 35 degrees, the AC light will not come on. If it's above 47 degrees the AC light is always on. Between the two it decides based upon memory, speed over ground, sensors, engine and air temps. The AC light does not mean the AC is on - it means it MIGHT be on or could come on when it feels like it.
If you push the AC button and it doesn't believe you need AC -- it will blink twice and go off. Really. And it's pointless to argue. Just lay back and enjoy.

If you insist on your way, there is Manual Mode. Which is still held to the same rules as above but you get to press more buttons and there are more pictures on the screen. You don't really get to turn on AC. You can only turn it off.

Honest. It took me a year of screwing with it to learn to just set the temp and leave it alone.

 

That would be fine if the stupid thing would actually blow cold air! When it's 70 outside and a lot hotter than that inside the car after it's been parked, the A/C still doesn't come on most of the time no matter how you set it. That's what bugs me so much about this. Keep in mind that last week it was too cold to need the A/C, so I still don't know if the system is really even working "correctly".

 

Are you able to control your vents? I mean, can you go from "head", to "head/feet" to "feet only" and have zero air come out of the "head" vents when it's set to "feet"?

You should have a code if you have the correct pressure in the system LOW AND HIGH and you're able to control the vent direction I would think.

 

So, what are the outside temps when you are trying this? I think mine is a little flakey as well, but am still learning, or trying to. I don't think it will throw any codes for the pressure issue? My biggest prob is when its around 60-62 outside, and it doesn't seem to know what to do, I know what I want but it doesn't seem to translate very well.

 

Yes, the controls work correctly. I'll check again for codes again this morning.

 

Yep, that sounds familiar...........

 

The HVAC unit sets itself to 73 degrees if no other input is available. It also tries to go to how it was previously set if that info is available. If your outside air temp sensor is bad or disconnected it sets itself to 56 degrees. This means it will never turn on the AC.

I read this procedure here and have tried it with some luck: You really should be driving the car when performing this procedure. There are speed sensors involved and it's not that precise. Just do it SLOWLY.

In AUTO - SLOWLY turn the driver's temp control from the starting point of 73 degrees down to 60 in 2 degree increments - SLOWLY. When it gets to 60 degrees (and if it feels like it - see previous post) the AC should come on. Let it run for a few moments.

Then SLOWLY in 2 degree increments raise the temp until the top setting of 90 degrees showing. The AC should have shut off and the heat should have come on during this procedure. Let it run for a few minutes.

Then SLOWLY turn the temp down to your comfort level - somewhere around 73 degrees. It should stablize. It doesn't like it when you crank the temp **** too fast. I leave mine at 68 in the summer for AC and 75 in winter for heat with minor adjustments. The passenger **** only changes that side's temp about 5 + or - degrees from the driver's setting.

Or I shut the whole thing off and ride with the windows open and the radio on loud.

 

Thanks, I'll try that. I do have a problem with fiddling with the temp control too much. Luckily, my radio goes to 11.

 

Turns out a had a weak relay for the A/C clutch. Swapped it with another one in the fuse/relay box (horn I think it was) and it's fine now - the horn works fine too.