Next on my (endless it seems) list of problems is the climate control.
The unit displays, moves flaps, controls fan speed (in Auto mode), etc. But won't get really warm (I'd say 65 deg F).

Here are the codes, that return quickly after each reset:

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04162
Shop #: WSC 06325
VCID: 29570979F97F

4 Faults Found:
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus

All 4 codes seem to deal with wiring issues.

Where are the wires and ground connections I should start checking, and what do I need to look for?
Where are sensors (Footwell, Center) located and how do they look like?
Where is signal for coolant temperature coming from? From a sensor (which/where?) or via ECU (which wire?)?

 

Decide (due to the number and what seems erratic appearance of codes) to get another used module for trail/error.

Installed module yesterday (unknown history, so I don't have final proof; could be just another bad HVAC module). When taking console apart, I noticed that there is a small fan, connecting to tube to the small center slot of the center console. In that slot is a temp sensor.

Below are the most recent codes before and after the switch. Some are the same, at least one is different (which could be from wrong install since it deals with the dash temp sensor):

The way I see it:
a) another bad module
b) module (or both) are ok, individual sensors issues
c) module (or both) are ok, sensors are ok, but wiring harness or connector or ground issue

Is it now time to attack each code individually?
Are those codes common (i.e. sensors fail)?
Aside from the 4 or so connectors in the back of the unit, and obviously the various sensors (with connector I assume), are there other elements/connectors in the path?
Where are the referenced (in the codes) sensors located?

New module 040911

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 B
Component: A4 KLIMAVOLLAUTOMAT_D73
Coding: 04142
Shop #: WSC 06335
VCID: 27530F41EF6B

5 Faults Found:
00785 - Temp Sensor in Instrument Panel (G56)
30-00 - Open or Short to Plus
00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent


Old module 031111
-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04162
Shop #: WSC 06325
VCID: 29570979F97F

6 Faults Found:
00779 - Outside Air Temp Sensor (G17)
30-10 - Open or Short to Plus - Intermittent
00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus