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Discussion Starter · #1 ·
I am purchasing a neighbor's 1991 9000CD. The ACC has a significant problem, and am looking for info.

Problem: ACC starts cold, then about 2 -5 minutes after starting, the dampers close (you can hear them close), and it goes full hot. At the same time, the ACC compressor cuts off. Running the diagnosis/reset resets it to cold, again for about two minutes. This same behavior also happens in econo mode.

Have tried reset/diagnosis of the system, no error codes are displayed.

Would this be a symptom of a sensor misreading, a mechanical failure with one of the linkages controlling the dampeners, or the ECU unit itself?

Don't be afraid to be very technical in your response; I am a former mechanic as well as a Computer engineer.
 

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Discussion Starter · #2 ·
OK, so here I am replying to my own post...

A little more about my background...

I currently drive a 1984 Saab 900S, approaching 240k miles on it, but the gearbox is wearing out, the front main seal is leaking oil, and I would rather upgrade to a 4 door with turbo than drop a large amount of cash into the 900S (I have no garage).

Anyway, a neighbor has a 9000 CD Turbo which I am buying, excellent price, but has the Air con prob mentioned in my earlier post. It is equipped with ACC2, and I would like to know how to daignose which sensor/component would cause it to start cold, then have it go full hot. You can hear the temperature control flap close, and the AC compressor shuts off. Self Diagnosis reveals no failures.

Any help is appreciated.
 

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Welcome to Saabscene

Only a thought from reading other comments as I have a 9-5.

The two minutes of cold could be just the system waiting for the engine to heat up. The full hot after that sounds as if the internal temp sensor is not giving the right signal. I believe it's in the dash behind a grille and has a fan that sticks or gets noisy. I would look there to start with. Check the fan is going - on a car that old I would suspect that if it's not noisy, it's stuck and blocked with fluff. Then check the sensor itself.
 
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