A month ago after driving for only 30 minutes or so, parked in my
garage and an hour or so later went back to investigate a noise. The
aux fan on my 2005 ML350 was still running.

I started the car and turned it off again, then after a minute or so
the fan went off. A week ago, got in to go home from work and the
battery barely had enough juice to turn over the engine and would not
start the vehicle. Got a jump, drove home and the aux fan kept running
- again. I had to disconnect the harness to stop it.

I have been driving around for now with the aux fans disconnected --
have not changed  or charged the battery -- and everything seems to be
fine. Has anyone else had an issue like this? Will leaving the aux
fans disconnected lead to more serious problems? The car does not seem
to be running hot or anything like that...