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Discussion Starter #1
I having problems going on with my air conditioning. Sometimes it will stop blowing out of the vents and then sometimes it blows great. I've had the control panel replaced. At times I notice fog coming from the vents. This doesn't happen all the time. The dealer can't figure out what's wrong, they tell me to bring it in when the problem is happening. But when it's happening and by the time I get to the dealer it's working fine again. Crazy! Do anyone have any suggestions or ever had this problem? Please respond, thanks.
 

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Is there a check valve on the power brake booster anymore? If so, in the older cars that has proven to be a fault of some strange a/c behavior. You might look and see. Just for grins and giggles if nothing else.
 

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Does the airflow stop in all modes even when the blower is still on? It could be that your evaporator core is icing over. When the problem happens, open the hood and look at the low side A/C line (its the larger of the 2 lines) and see if it has ice on it. It may be that your A/C compressor is not cycling on and off properly.
 

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Does the blower motor actually stop, but the air still breezes out of the selected mode? i.e.- panel, floor, defrost, etc?
Is this an ATC or MTC system? What was the diagnosis on the control panel or was it a guess?
Have you owned the vehicle since new and has the A/C system ever been serviced?
 

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Discussion Starter #5
It stops blowing AC and Heat out of the vents when it acts up. Sometimes fog comes out of the vents first. I can turn the car off about 15-20 minutes and then it starts blowing great again. It does this in all modes. I just bought the car, I've had the car about 2 months. The blower stays on, at least I hear it but no air comes out of vents, defroster, floor etc. The control panel was a pure guess, didn't solve issue. Tech at the dealer stated that it has a leak at the elbow and the evaporator needs replacing. I'm going to get an 2nd opinion. Thanks guys, I will ask the techs about you'll suggestions.
One more thing, what do you'll think about installing a cool air intake? Any suggestions would be appreciated. Thanks.
 

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It sounds as if the evaporator may be icing up in humid weather and blocking airflow? The fog coming out the vents and the resumption of operation after a 15-20 minute thaw, may be a clue that this is happening.
There should be a temperature probe in the evaporator the turn off the compressor when there is danger of freezing. It may be malfunctioning. The dealer may find stored codes even if the system is working OK when you get there.
A cold air intake is unnecessary. The factory air cleaner already has a cold air set-up and you will gain no advantage.
 

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Discussion Starter #7
Thanks, if you had to guess would you think replacing the evaporator and searching for any leaks would fix these symptoms I'm stating? Or do you think that it sounds like a compressor issue? Just, if you had to guess. Thanks.
 

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The pressure and temperature sensors and electronics that control the compressor cycling on/off usually keep the compressor from over-cooling the evaporator. It should be kept ~34°F or above. The sensed evaporator temperature can be read on a good scan tool.
The HVAC electronics can run tests, diagnostics, calibration and store fault codes with the dealer scan tool (or proper equivalent). Any known fault codes from the last service?
Any leaks will cause low pressures and must be fixed first. The refrigerant must have a closed system to operate in (low pressure=low temperature).
If the previous diagnosis condemned the evaporator (for a leak?) and an A/C (elbow) line leak, they should probably be replaced first. These may be your only problem if this is an accurate diagnosis.
If someone else is going to re-diagnose the problem, compare their findings to the original findings.
A/C evaporator service is expensive.
 

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Discussion Starter #9
Ok thank you very much, very good information. I will keep you posted with details. I'm getting a 2nd opinion tomorrow.
 

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Even a low charge can cause freeze up under some circumstances. Running the fan on higher speeds can reduce or eliminate this problem too in spite of other problems, but you will have to have this thing checked out and corrected.
 
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Discussion Starter #11
Hey...they finally resolve my A/C problem, the temp probe was malfunctioning. It was not allowing the compressor to cycle on/off. Thanks for bringing that to my attention, I ask the Tech to check that out and sure enough, that was the cause of my system freezing up. Thanks again guys.
 
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