Today I picked up a set of extraction tools that are said to be good for all German radios. Tomorrow, I'll put some heat in the garage and see how much farther I can get in reaching the recirc air switchover valve.

In the mean time, I've been studying the service manual section on the HVAC system.

As far as I can tell, the recirc air switchover valve simply applies vacuum to the actuator for the flap which switches the air flow to the blower from outside air to cabin air. I don't find any information in the manual as to which mode is enabled when vacuum is applied to the flap actuator. I'm also not finding any reference to the flap's actual location in the manual either.

I'm hoping that when I get access to the recirc air switchover valve, I'll be able to follow the vacuum line to the flap actuator.

If anyone knows which function is enabled when vacuum is applied, please let me know.

- Bill