TDI A6: AC Relay Flutter - Troubleshooting

Hello everyone,

I have an A6 C4 with automatic climate control. I've been driving it for 4 years now. Sometime last year, the relay for the air conditioning system started intermittently failing (electrically), sometimes disconnecting and then reconnecting, etc... Then it would be gone for a few days or even longer, only to reappear again. When the relay fails, the corresponding fan also stops working.
I then had the coolant replaced, including the expansion valve. At the same time, I also had the air conditioning system evacuated. I wanted to make sure that no refrigerant was being lost through any leaks, which could have caused the pressure in the system to be at its limit. Besides, it was due for a service anyway...
However, everything was fine, and the problem was therefore not resolved.

Now there are pressure switches in the climate control system. Can anyone tell me where the pressure switch(es) is/are located?
I would like to be present with a measuring device the next time this problem occurs again.
Perhaps the switch(es) are malfunctioning.

Or does anyone have another idea, or are there any known issues with these vehicles?


Thank you and best regards.
Wool.

Oh yeah... I forgot... (sorry!!!)

Okay, so the error memory is clear. The system shouldn't be overloaded either. I already had that checked after contacting support.