I searched through the archives but could not find this question already answered

My ACC, specifically the a/c is turning off for no apparent reason, on both the AUT and regular fan positions. When it goes off, it totally shuts down and will not turn on again, but the lights do not blink which indicate a problem. If I turn off the car and restart it, it works again. My gut tells me the unit is going bad since the system was professionally charged and it seems like an electronic bug.

Is the brain of this system contained in the box with the controls? To me, that is the obvious thing to replace since it is a self contained unit.

Thanks

I don't think you have enough proof that the ECC is the culprit to justify replacing it. I don't think it is very common for the ECC to fail. What do you mean the A/C totally shuts down? Is the compressor turning (watch near the compressor clutch)? Does the fan blower turn off by itself? What is the refrigerant pressure when it is running, when it is off? Will it come on if you short out the low pressure switch in the line near the firewall? (remove the connector, put a paperclip in between the contacts, don't let the clip touch anything else, like metal). When was the system "professionally charged", and WHY did it require charging? Did you have poor performance before? Did the problem arise soon after the PRO worked on it? The ECC fault lights will NOT show a fault for improper refrigerant level. My theory is your PRO improperly charged your system. Or sabotaged it. But I'm a pessimist and don't trust people with my vehicles. Perhaps you have a massive refrigerant leak.

thanks - the system was recharged due to the evaporator going bad, which I replaced, along with the o-rings and accumulator as well.

What happens is the a/c is running fine, then the fan just stops, as if receiving a signal to turn off. This happens on both the AUT and regular fan speed modes. The a/c compressor also turns off. Even if it were improperly charged, or not charged at all, the fan should still not be stopped - it should just blow warm air. If I turn up the temp switches to hot (and turn off the a/c switch), the fan will still not come on. Only when I stop the engine and restart will it be "reset" and work for a day, few hours, or ten minutes before shutting down again.

Today, it blew cold as normal, but did not react to increasing the temperature, whereas before it did (before it would shut itself down, of course). This is a new development, making it seem even more likely the control unit is dying/dead. Thoughts?

Could be a plethera of possibilities, but when I hear of this symptom which I have seen before, it tends to be too much gas in the system. It cools fine for awhile until the unit freezes up and it has to thaw out before it will work again. Just my thoughts and I could be wrong and it could be something else, like the gap in the clutch in the compressor. Search here and you'll find many posts about that problem too. Get your gas pressure checked.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon