I was sitting at a stop light and I pressed the window up button (the window was already up.. i was fiddling around) and the lights in the cabin dimmed and I could hear the alternator whine get louder until I released it...

I also believe the headlights dim a little bit as well when I hold the button down when the window is already up...

Is this normal?

 

sometimes i think i even see the voltmeter drop a little.