Had this happen recently on one of the kids Subaru Outback...
He noticed that the ABS light was flickering... next he said that he had no low beam headlamps..
Next morning it would not start...
So off he went to school in my 190D
An investigation started..
Low battery voltage and upon jump starting the car, I was getting 13.5v... all seemed good...
We suspected the battery, so it was checked and one cell was low.
I checked the headlamp bulbs and both were blown....
I was on alert, and something else was going on as they were only a few months old...
This car has daytime running lights... the low beams.
Got a fresh battery, and it was then that it all became clear.
A quick test when the engine was started showed 16v at idle!
At 1500 rpm it was 18v and climbing!
Removed the alternator, and found the charge terminal was loose!
Replaced that and the headlampos and all is well.
I bet the blower motor took the brunt of your overcharge issue and it fried it!