[V8] Still Freezing my Feet off...

[bob moy]

The following is from chris Miler's website

http://members.aol.com/c1j1miller/  check the motor which controls the 
Temperature regulating flap.

Temperature regulating flap

The climate controller head regulates temperature by cycling the air 
conditioning compressor on and off (unless set to "off" or "econ"); by 
turning the flow of hot engine coolant to the heat exchanger core on and off 
via a valve located behind the engine head on the firewall; by closing the 
recirculate flap behind the glove box; and by controlling airflow using a 
temperature regulating flap. The flap is located under the hood, beneath the 
black plastic plenum on the firewall.

The climate control head controls an electric motor with a feedback circuit 
that tells the control head the flap position. I've found that if the 
electrical connection to this motor degrades, the climate control head 
cannot properly control the flap positions. You'll notice this when you get 
too much heat, or no heat at all. Run the climate control diagnostics 
(below) for details.

This motor has an audi part number of 443 820 511 A (Bosch 0 132 801 003) 
and runs around $70.

The fix involves either replacing the temperature regulating flap motor, or 
using electrical contact enhancer to improve the connection at the harness 
under the plenum.

Start by opening the hood, and removing the windshield washer arms (pull the 
protective caps, remove the 10mm nuts, mark the position of each wiper arm 
on the windshield, then bend each wiper at the joint and pull them off. 
Remove the couple screws holding the wiper assembly in place, and set it 
aside. (This gives you enough room to work, and only takes a minute to 
remove.)

This is a good oportunity to pull out the shop vac and remove all the dead 
leaves, small animal nests, and years of dust and debris. You'll need to 
make up a small diameter extension to get down into the bowels of the 
system; I used a paper towel roll cardboard.

Lube the moving parts/joints for the flaps. The motor is located on the 
driver's side of the blower box, above the glove box area. Follow the wiring 
back along the engine compartment wall; unsnap the connector, and use a good 
contact enhancer/cleaner; then reconnect. Now, start up the car, and run the 
climate control through the various settings and temperatures to make sure 
everything moves smoothly.




[V8] Still Freezing my Feet off...
robert_a_dupree at bankone.com robert_a_dupree at bankone.com
Mon Jan 24 10:35:20 EST 2005

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So I think I've got a problem with the replaced heater-core, flaps,
temp-sensors or controller mechanisms.
The car gets warm in both oil (80c) and water temps (90c).
My seat heater gets warm, so that's not a problem.
Even when leaving the temp set to "HI" and the Blower on "Low" the air
coming from the vents on a 25deg day feels at best 40deg.
This is true for defrost vents, dash vents and foot vents.
The temp differential over ambient seems to be constant so the car
eventually gets above 60deg on the inside, except for the foot area.

I come to the conclusion that either:
1.  There is minimal hot engine water flowing into the heater-core because
of a valve problem
2.  No hot water in core because the HVAC controller is sensing the output
air incorrectly
3.  Plenty of hot water in heater core, but no air flowing through.

So can someone scan the couple of basic diagnostic trees from their V8
service manuals?
Before I finish putting all the lower trim panels in place I'd like to get
this resolved or at least improved.

Help.