<E-34> Air Conditioning Failure

["Brant M. Miller" <brant@xxxxxxxxxxxxxx>]

Thanks to those of you who offered advice in response to my previous
request.  I could use additional input, if anyone has a thought to share.=


My problem is that my AC turned itself on.  The AC and air recirculation
switches were off, but the AC compressor was running.  The refrigerant
return line to the compressor frosted up.

I took the car into the dealer yesterday.  They hooked it up to their
portable MODIC unit and looked for problems.  They found none.  Their tec=
h
said that frost-up of the refrigerant line leading to the compressor was
not unusual.  Apparently, they did no other testing.

I suspect that frost-up of the refrigerant line is quite unusual - at lea=
st
my system has not done that in the past and is not doing it today.  I nee=
d
to become smarter, but I believe that the various pressure and temperatur=
e
sensors that feed the Integrated Climate Control Module cause the
compressor to cycle such that frost-up does not occur.  If I'm correct,
then my failure is downstream of the ICCM.  Only the Engine Control Modul=
e
(DME), the compressor clutch relay, and the compressor seem to be
downstream of the ICCM.  Curtis suggests mechanical failure of the
compressor clutch.  I'll try to put a VOM onto the relay when the problem=

recurs.  That should rule clutch failure in or out and may provide some
information on the relay too.

Any other thoughts?  What has been the Digest's experience with late-mode=
l
DMEs?  Have many failures been experienced?  Does anyone know for certain=

whether or not frost-up of the refrigerant return line is "not unusual"?

Any comment will be appreciated.

Brant

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