I was sitting in the parking lot with the car in neutral and the E-brake on and the windows were up. I thought they were down so I tried to roll them up and when I pressed the window switch my RPMs dropped by about 100. At the same time, my headlights got a little brighter. When I let go, the RPMs went back up and the headlights went back to normal. Is that normal? It seems kinda weird because headlights and windows are electrical. If its not normal, could it be a sign of a problem either with the engine or the electrical system? Thanks for the help guys.

2000 A4 1.8TQM

 

ya it's normal.

 

does it to me all the time

even though they are not related, you are putting a load on your alternator when you try and roll your already rolled up windows up, and there is a "power surge"

+1 on normal

 

its the secondary air pump/injection (sai). Its used to warm up the engine faster. You will hear it and see ~300 higher rpms when its on (1100rpms vs 800rpms). Its on all the 2000+ cars.

 

sometimes mine(1999) does that,goes from 800 to 1000 or so,just standing on a light,wonder what is that all about