RE: CC codes? Not sure of itself?

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

... actually, the way the system is designed to work coolant is supposed to
flow through the heater core anytime except 1) when the system is in "AUTO"
and the A/C head temp is set to "LO" or when the head is set to "OFF" ...
the blend doors duct air through and around the heater core to adjust the
temperature.  If you get warm air at any setting other than "LO" I suspect
that you've got a problem with the motor on the A/C programmer that drives
the Bowden cable hooked up to the blend doors.  You an test this fairly
easily by pulling up the plastic cover over the blower box and having
someone adjust the inside air temp.  The Bowden cable is attached to the
right side of the blower box (i.e. opposite the blower motor).  Most
everything around it is white, and you'll see a shiny cable attached to a
mechanism on the blower box.  As the temperature is adjusted from HI to LO
you should see the cable extend and retract.  The drive motor and
potentiometer for the Bowden cable are fairly notorious on these cars.  

As Phil did point out, there is also some chance that there is no vacuum
applied to the heater valve.  While I don't think this is the case based on
your description that when you have the system set to "LO" it does cool
down.  IME the source of the lost vacuum is from the vacuum motor that opens
and closes the fresh air/recirculate doors.  This motor is on the same
vacuum circuit as the heater valve, and when the recirculate door sticks
closed it will rip the vacuum motor from its mount, and often disconnect the
vacuum line at the same time.  You may want to look for this on your car if
you don't know if the recirc door/spring has been repaired on the car.  

While I'm talking about the subject, let me pass along an idea that I plan
to do to my '88 Avant when I put it back together ... I suppose I should do
it to the V8 as well ... Since I usually use the HVAC in the "ECON" mode I
find that the fact that coolant flows through the heater core at all times
makes it a bit warm in the summer time.  What I am planning to do is to
install an old-style manual heater valve in the line to the heater core.
What this will allow is for me to manually control the amount of coolant fed
to the heater core, so I can throttle it down during the summer and turn it
back up in the winter simply by popping the hood and moving the valve.  

HTH!
Steve Buchholz
San Jose, CA (USA)

> ----------
> As to the unrelenting heat: sounds like you've lost the vacuum connection
> to your heater control valve located at the left rear of engine
> compartment
> (no, your _other_ left*) and/or it's stuck in the full-hot position.
> 
> >
> >My CC has been acting real werid(The CC gives me warm heat for all of the
> >setting except Auto/below-LO), and I decide to pull the code.  When
> coding it
>