Since most of the people on here probably don't have automatic climate control its probably just useful for europeans and the ones doing a conversion. But yes the automatic climate controls do have their own diagnostic mode. It can give you error codes for the electronic system.
Steps to activate:
(1) Ignition on
(2) Set the fan speed to AUTO
(3) Turn the fan on the windshield (all the way to the right)
(4) Briefly press the red button and AC button simultaneously and release again
(5) Briefly press the blue button
(6) Then "strange" characters appear, that takes about 30 seconds.
(7) The error is then displayed
Error Codes:
20 22
Short circuit in heater flap servomotor circuit
24 25
Fault in the heating flap servomotor control
30
Short circuit in the interior sensor circuit
31
High resistance interior temperature sensor
40 42
Short circuit outside temperature sensor circuit
41 43
High resistance outside temperature sensor circuit
50 52
Short circuit in sun sensor circuit
53 59
Sun sensor measured value is not supplied
60 62
Fault in the interior temperature sensor of the fan circuit
63 69
Indoor temperature sensor measured value is not supplied
70 72
Short circuit in engine cooling temperature sensor circuit (air conditioning)
71 73
High resistance in engine cooling temperature sensor circuit (air conditioning)
88
NFF (no error found)
90 99
Internal error
Credits to
@RedCougarGirl. She has alot of Instruction on her site
redcougar.de. Unfortunately its all in German but Google Translate can help you guys with that haha.