2003 E65 730d - sudden heat increase at driver's side only with AUTO on
I've been experiencing this very weird climate control problem for which my beamerdealer could not give an answer, since he has never experienced this before. It all started when driving long distances at high speed on the Autobahn last summer. Although I had my climate control on AUTO and the A/C was on (control light burning) and the passenger's climate control was not on auto but at a steady blowing speed and temp of 22degs, I suddenly experienced very hot air at my feet and under the front window. From the front vents oriented towards the driver came a 'bit colder' air, but still not A/C-cooled. When I pushed the AUTO-button, AUTO did not turn off. When I turned the blowing speed-button, blowing speed adjusted (although still hot air) but AUTO-light remained on, which should normally turn off. The passenger's side did not experience any change in temperature regulation! So, the above weird story only holds for the driver's side...maybe, because the passenger's side never had the AUTO-button on (my wife prefers to stay in control herself ;P Stopping the car and turning off the engine or even leaving and locking the car did not resolve the problem after restarting the car. We had to turn off the engine, throw 2 buckets of water on the bonnet and then restart. Throwing buckets on the window did not help...the water really had to hit the bonnet. The outside temperature remained correct throughout the whole procedure (40degs Celsius...HOT!).
This sudden warming up of air at the driver's side also occurs now, when it's colder. So, the A/C is turned off, but the AUTO at the driver's side is on, and then, all of a sudden, the driver's side is heated up.
The most annoying issue at the moment is that I did not find any systematic in WHEN all this occurs. Sometimes it occurs during an easy-going highway drive, sometimes during high speed highway drive, sometimes 10 minutes after a highway while driving at a city speed. It occurs during a hot summer and during current fall temperatures.
Does anybody have any idea? I fear it would be an extremely expensive problem to diagnose, since it sounds something software-like.
Thank you very much for any relevant info!