I have an issue that I'm clueless on. When rolling down the windows the voltage gauge will drop and if the ac is on the fan will slow down with the voltage drop. I put a multimeter on and got the following results:
- Car off 12.69v
- Car on 13.60v
with the car running at idle the voltage will drop to 12.93v when rolling down the windows and the ac blower fan slows down as well. The motor also acts as though there is a load applied.
with the car at 1800rpm the voltage drops to 13.37 with no effect on the ac blower fan or engine.
The alternator is new, and the battery was purchased from Walmart the beginning of this year.
Any suggestions on what to look at would be greatly appreciated.
2001 chevy suburban 1500

 

I would consider that normal at idle

 

That all seems normal to me as well. The window motor presents a pretty sizable load to the system that will be noticeable at idle, or with the car off.