Hi , I posted on the E39 forum an issue where when I opened and closed the doors or boot the Webasto aux heater attemped to start.
The answer I got was as follows..
What has been seen to happen is when the alternator wears as the door opens the voltage drop in the system sends a earth back feed to the heater. Hence you hearing it attempt to start. The heater will appear to run for a couple of minutes as it will go through a run down sequence.
So my question is 'what exactly is the wear' is it doides, brushes or mechanical.
The alternator is working re-charging the battery and I have never had any battery issues.
Any observations would be appreciated