Climate control does not communicating with any module

[diwasas]

Hi,

I'm having a problem with my climate control unit. According to VCDS, unit does not communicating with any module, though unit itself is working fine (heating, seats heating, rear window heating, except mirror heating).

Address 08: Auto HVAC        Labels: 8E0-820-043.lbl
   Part No: 8E0 820 043 C
   Component:   A4 Klimaautomat   0712  
   Coding: 00000
   Shop #: WSC 63351  
   VCID: 2149030FAB3C3116BBD-5072

5 Faults Found:
01317 - Control Module in Instrument Cluster (J285) 
            49-00 - No Communications
01330 - Central Control Module for Central Convenience (J393) 
            49-00 - No Communications
00466 - Control Module for Steering Column Electronics (J527) 
            49-00 - No Communications
00457 - Control Module for Network (J519) 
            49-00 - No Communications
00474 - Control Module for Immobilizer 
            49-00 - No Communications

I've tried to replace with other climate control unit for testing and got another fault code "incorrect chasis number (VIN)". Logged in with VCDS into HVAC -> Adaptation -> ch 081 and there was a message "Bus Not OK", and ofcourse when I enetered a code for "vehicle data learning" I've got a message "ERROR" :)

Any advices where to start looking for problem?

Can this communication problem be a cause for not working mirror heating? (there is no voltage to the mirrors, though rear window heating is working fine).

[diagnosticator]

The CAN buss is not connected to the Klimatronic Controller. There is a wiring fault somewhere, involving both the Comfort CAN Hi (Orange/Green) and CAN Low (Orange/Brown) wires, otherwise the CAN would be connected and functional in single wire mode. The two CAN wires need to be traced backwards from the Klimatronic module, using an Ohm meter checking for loss of continuity in the CAN wires.

Comparing the wiring diagram with the controllers not communicating with the E87 klimatronic controller, the circuit fault is at or between the E87 klimatronic contol module and the other controllers shown on the list of DTCs as not communicating with the E87 controller on the Comfort CAN Buss.

Mirror heat does not depend on CAN functionality or the Klimatronic controller, it is independent.

[diwasas]

The CAN buss is not connected to the Klimatronic Controller. There is a wiring fault somewhere, involving both the Comfort CAN Hi (Orange/Green) and CAN Low (Orange/Brown) wires, otherwise the CAN would be connected and functional in single wire mode. The two CAN wires need to be traced backwards from the Klimatronic module, using an Ohm meter checking for loss of continuity in the CAN wires.

Comparing the wiring diagram with the controllers not communicating with the E87 klimatronic controller, the circuit fault is at or between the E87 klimatronic contol module and the other controllers shown on the list of DTCs as not communicating with the E87 controller on the Comfort CAN Buss.

Mirror heat does not depend on CAN functionality or the Klimatronic controller, it is independent.

Today while soldering radio wires, I found, that both CAN wires for climate control were cut down. Soldered them back and all fault codes gone.

And most importantly: Mirror heating is working again. So I think if climate control cant communicate with Central Convenience module mirror heating wont work.