My a/c was checked recently for not blowing cold air. Of course it goes
the first hot day of the season. Everything checked out
OK at the mechanic but they said I needed a new ECU. Everything else
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
computer went bad the car would just not run at all.
They quoted a high price  but I noticed that autozone has them for
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
you have to use the old PROM and put that in the new ECU module, does
sound correct? Just disconnect the negative battery cable before you
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
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?
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!
Well they do advertise a standard AC checkup, so I figure they could
if the compressor was bad or not. Don't know. It is the original
however, so that's definitely a possibility.
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.
I have a '95 Park Ave, and it has an AC Programmer. I happen to know,
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
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