david.hierro

Hello everybody!

I've been looking at the opened threads but did not find anything related to this problem...

I've recently adquired a second hand A4 B9 Avant with 15.000km. The car is just perfect. It does not have all features I'd like but I can live with it. However, one thing I am a bit dissapointed with is that it has the basic climate controller (the analog monozone one). It works fine but in my opinion is totally out-of-style...

I found the digital one through Internet (8W0 820 043 G) and just received it. The installation was quite straight forward and it worked fine until I turned on the car

After that the digital climate controller turned off and the off button started blinking.

It seems to me that once the system initializated it detected a non registered feature and it just disabled it. I'like to know if this feature can be enabled somehow (OBD, ...). Otherwise I'm afraid I'll have to return it.

At the moment I've reinstalled the analog climate controller...

Thanks!!

wdimagineer

The digital controller requires additional hardware your vehicle doesn't have, including an upgraded compressor, compressor clutch, and added fans to circulate air into the extra zones. Unfortunately you can't just use the digital panel to control the lower end system.

A retrofit to the 3-zone system would in theory be possible, but the amount of parts required would likely not make much economic sense.

david.hierro

I knew that the addtional zones air circulation would not be enabled as the car is not prepared to but I thought that at least I could control the main temperature/features.

The interesting thing is that after upgrading the module everything worked fine (the digital controller worked as expected, cold/heat, basic zones, ...) until I started the engine and the system initialized. After that I believed the system detected the HW change and disabled the module operation.

wdimagineer

You're certain it was actually working? Did you adjust fan speed and notice a difference? Adjust airflow direction?

Your hypothesis about what happened is correct. There are subtle differences between ignition on and engine on when it comes to vehicle systems checks. Since the air conditioning compressor is dependent upon running the engine, when the system detected an implausible situation it shut it down to prevent component damage. We design these failsafes intentionally.

david.hierro

Yes, it worked. I tested the airflow regulation (manual button and also depending on the temperature) and the up/down/middle air direction distribution. Increasing/decreasing the temperature in both left and right controllers caused the same behaviour (I was expecting that right passenger controller would not work).

I suppose I'll have to return the module

wdimagineer

It worked because certain functions are mapped in software at the same logical addresses between the modules when they talk to the car's systems. However, the handshake that occurs (and must be satisfied) is different. I don't think this can be coded because the base A/C hardware doesn't know how to communicate with the digital module as the software is different. It won't respond in the manner the system is expecting, and it will shut it down.

strelec1234

johnmili

Fernando Bisca

johnmili