2002 Audi a4 B6 Climate control module swap

[jdog6973]

I have been having problems with my HVAC system not producing heat for the past month. I ran a scan, and none of the flapper motors returned any codes. I connected thermocouples to the heater core's inlet and exhaust tubes, and the temperature is reaching 200°F. Today, I read a short post at https://forums.ross-tech.com/index.php?threads/22776/ , and the person there was experiencing the same issue I am. I'm hoping Uwe will chime in and point me in the correct direction. This is my old module https://i.postimg.cc/vT7NG0cx/HVAC-Old-Module.png but I can not find how to correct the coding in VCDS. I have added all zeros for, but not sure if I need the shop code from my old module. Everything works except the rear window defroster. When I press the button, it comes on for 2 seconds and shuts off. my old HVAC module was part number 8E0 820 043 G, and the new module is an 8E0 820 043 BM . any direction would be appreciated.

Friday,06,February,2026,16:57:15:06014
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 25.3.2.0 (x64)  HEX-NET CB: 0.4671.4
Data version: 20250822 DS365.0
www.Ross-Tech.com

Dealer/Shop Name: Downs's Shit Show

VIN: WAULT68E52A132589   License Plate: 


Chassis Type: 8E (8E - Audi A4/S4/RS4 B6/B7 (2001 > 2008))
Scan: 01 02 03 08 09 0F 11 15 16 17 18 25 36 37 45 46 55 56 57 65
          67 69 75 76 77
 
VIN: WAULT68E52A132589   Mileage: 383830km-238500miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 06C-909-559-ASN.lbl
   Part No SW: 8E0 909 559 D    HW: 8E0 909 059 
   Component: 3.0L V6/5V      G   0003  
   Coding: 0016751
   Shop #: WSC 63351 000 00000
   VCID: B6206247C050832BB9-5160
   VINID: 9D195C9062151424410C2148248A5244CF

No fault code found.
Readiness: 0110 1101

-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 01V-927-156.lbl
   Part No: 8E0 927 156 Q
   Component: AG5 01V 3.0l5V  USA 1213  
   Coding: 0001002
   Shop #: WSC 02609 444 58946
   VCID: BC34706FFE7C597B4F-5160

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 8E0-614-517.lbl
   Part No: 8E0 614 517 A
   Component: ABS/ESP allrad      1726  
   Coding: 04497
   Shop #: WSC 06435  
   VCID: A600B20740F0F3AB09-51F2

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 8E0-820-043.lbl
   Part No: 8E0 820 043 BM
   Component:   A4 Klimaautomat   3233  
   Coding: 00000
   Shop #: WSC 00000  
   VCID: ED928D2BA58600F388-5160

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels: 8E0-907-279-8E2.lbl
   Part No: 8E0 907 279 E
   Component: int. Lastmodul  USA 0305  
   Coding: 00013
   Shop #: WSC 63351  
   VCID: B424584F862C913B87-4B1E

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 8E0-959-655-84.lbl
   Part No: 8E0 959 655 A
   Component: Airbag 8.4E         3000  
   Coding: 0010607
   Shop #: WSC 63351 000 00000
   VCID: B522654BDD568833B0-5160

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 8E0-953-549.lbl
   Part No: 8E0 953 549 L
   Component: Lenks ulenmodul     0308  
   Coding: 01141
   Shop #: WSC 63351  
   VCID: BC34706FAE7C597B4F-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 8E0-920-9xx-8E2.clb
   Part No: 8E0 920 950 H
   Component: KOMBI+WEGFAHRS. RB4 D25  
   Coding: 03200
   Shop #: WSC 02609  
   VCID: AE104A276800BBEBF1-5184
   WAULT68E52A132589     AUZ6Z0A0248833

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr        Labels: 8E0-959-760.lbl
   Part No: 8E0 959 760 
   Component: Sitzmemory R2 F     0202  
   Coding: 00002
   Shop #: WSC 63351  
   VCID: F1AA915BBABEE413AC-4B3C

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor        Labels: 8E0-951-177.lbl
   Part No: 8E0 951 177 
   Component: Innenraumueberw.   0504  
   Coding: 00001
   Shop #: WSC 00000  
   VCID: EB9683339B920EC396-5118

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels:. 8E0-959-433-MAX.clb
   Part No: 8E0 959 433 T
   Component: Komfortger t T5B    0617  
   Coding: 11788
   Shop #: WSC 63351  
   VCID: C2C80E97CC982F8B05-4B00

1 Fault Found:
01134 - Alarm Horn (H12) 
            37-00 - Faulty

-------------------------------------------------------------------------------
Address 55: Headlight Range        Labels: 4Z7-907-357.lbl
   Part No: 4Z7 907 357 
   Component: dynamische LWR       D06  
   Coding: 00060
   Shop #: WSC 63351  
   VCID: 8444C88F950CE1BB77-4B9A

No fault code found.

End----------(Elapsed Time: 06:04, VBatt start/end: 12.4V/12.3V)-----------
------------------------------4 Faults Found-------------------------------

 

[Ziddywerks]

Coding will not fix your issue. The reason why your defroster does not work is because the unit is not compatible. You most likely have a unit from a b7 a4 in which they removed the relay in b7 vehicles that is causing this issue. that your having, it has nothing to do with coding. Here is the work around to resolve that issue:

DIY: Rear defroster fix for newer HVAC unit in early B6's

Background: early B6 A4's came with an HVAC unit which directly powered the rear defroster; later B6's and B7's use a relay. If you install a newer HVAC unit into an older B6 (either because the lack off an OFF button sucks, or because all of the soft touch paint on the buttons has peeled off...

www.audizine.com

 

[Uwe]

Many moons ago we had a 2002 A4 with a 3.0T. One obvious difference is that it was a 6MT. It had HVAC module part number: 8E0 820 043 G and it was coded 00000, just like your old one.

I think Ziddy is likely correct, that 8E0 820 043 BM is belongs in a B7 chassis car, but I'm not familiar with the nuance differences.

-Uwe-

 

[jdog6973]

Many moons ago we had a 2002 A4 with a 3.0T. One obvious difference is that it was a 6MT. It had HVAC module part number: 8E0 820 043 G and it was coded 00000, just like your old one.

I think Ziddy is likely correct, that 8E0 820 043 BM is belongs in a B7 chassis car, but I'm not familiar with the nuance differences.

-Uwe-

Uwe, you're the best! I'm glad there is a workaround it is becoming harder to get parts. I had an Avant 3.0 in the local junk yard, but they crushed it last month to make room. I was so sad. It has become a challenge to get 300K out of this old girl, with zero rust and all-new undercarriage components. I have owned it since 2004
.
Thanks again, and I will post if the relay fix works.

 

[Uwe]

I have owned it since 2000.

I don't think so.

-Uwe-

 

[jdog6973]

I don't think so.

-Uwe-

I fixed it, between AI and spell check, we are in trouble