buick air conditioner ECU problem

Hi,
My a/c was checked recently for not blowing cold air. Of course it goes out the first hot day of the season. Everything checked out OK at the mechanic but they said I needed a new ECU. Everything else
works ok on the car except the cruise control went out last year.
Can an ECU be bad for just a few specific things like that? I thought if the computer went bad the car would just not run at all.
They quoted a high price [400] but I noticed that autozone has them for about 100. An ECU seems to be something thats easily replaceable by myself. I've replaced chips in my computer, so an ECU shouldn't be too bad. I read that you have to use the old PROM and put that in the new ECU module, does that sound correct? Just disconnect the negative battery cable before you start?
Thanks,
itchy
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First what year, second exactly how is the ecu at fault relative to this problem?

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1993. 3.8 The reason I think the ECU is at fault is because that is what the Firestone mechanics said. The computer is not telling the air conditioner to turn 'on'. This sounded to me like a temperature sensor problem or a thermostat problem. A few years ago I had a 'lo pressure cycler switch' replaced [it sounded something like that] to fix a similar problem.
The Firestone guys said they could 'ground' it directly but that would eventually short it out, so it was better to get a new ECU. I have no idea what they were referring to when they mentioned the 'grounding' fix. Does that help?
itchy
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There are many reasons here, I don't think this is a " Firestone" job, lo freon, ac compressor relay, bad pressure switch, lots of possibilities, I'd get a second diagnosis from a shop that knows these cars and their ac systems, that is not Firestone!

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snipped-for-privacy@hotmail.com wrote in

No way its the ECU. Since the car is 13 years old, I say bad compressor. $700-$800 to replace.
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HB wrote:

Well they do advertise a standard AC checkup, so I figure they could determine if the compressor was bad or not. Don't know. It is the original compressor however, so that's definitely a possibility. itchy
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It is possible for the ECU to be bad. There are several driver circuits from the ECU. That said I would get a second opinion from someone that has the knowlege of the electrical circuit and the AC system. Shorting out the compressure clutch will determine if it will produce cold air but it could also blow the driver circuit.

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I have a '95 Park Ave, and it has an AC Programmer. I happen to know, because something's wrong in that area on my car. Perhaps that programmer is what the tech is talking about. It's something akin to an ECU, but separate from the one that controls the powertrain.
Ed

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