"Alpha One" wrote:
> It was changed to R-124a a few years ago by an AC shop. I,
> about a month
> ago, only let more gas escape to almost empty and refiled it.
> I checked three switches including the low pressure one and I
> think they
> should be either open or closed. I tested both states on each
> and it does
> not cause the clutch to engage. I am not sure if this is a way
> of testing
> If I apply a voltage directly to the clutch it will engage and
> the AC works,
> cooling the car.
> I wonder if it is the thermostatic switch. How can I access
> Thank yopu,
> > "Alpha One" wrote:
> > > The AC in my 92 Bonneville is not cooling at all.
> The clutch
> > > does not
> > > engage. Fuses OK, fan working. The pressure is well
> into the
> > > red on the low
> > > pressure side,
> > > but the compressor in not working of course. About a
> month ago
> > > I charged the
> > > system after I let it finish emptying completely
> with R-124a
> > > which it was
> > > using before. It was leaking through the valve, I
> replaced it.
> > > Any idea what
> > > it may be?
> > > Thank you.
> > >
> > > Tony
> > Could be a lot of things, when you open a the system to
> replace valve,
> > did you vacum the system down before you recharged it? Also
> have you
> > checked the the low pressure cut out switch to on
> recv/dryer? I
> > assume it was a R12 system that you converted over or was it
> > R134? And finally, a pressure reading in the red on the low
> side is
> > meaningless when the system is not running.
> > --
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> > Articles individually checked for conformance to usenet
> > Topic URL:
> > http://www.autoforumz.com/GM-AC-problem-92-Bonneville-ftopict125980.html
> > Visit Topic URL to contact author (reg. req'd). Report
> > http://www.autoforumz.com/eform.php?pa4020
GM does not use a thermostat switch, just a low pressure and high
pressure cut out switch. THey control temp by mixing air. The switches
are in series and normally closed for AC to work. If either one is
open it will not work. Jumper both accross and see if A/C works. If
not trace power back with a meter and find out where it is being lost.