Is this normal? - BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)

tonytigerking · 08-22-2008, 09:13 PM

Just noticed this today in a long traffic jam. With my a/c on, I noticed that it creates a light vibration when I press the brake down, and I can hear what seems to be motor-like noise along with the engine noise. I've never experienced that with my other cars.

ML · 08-22-2008, 09:35 PM

Yes, it is normal. The charging system operates only under braking. What you heard was the alternator engaging as you depressed the brake pedal.

tonytigerking · 08-22-2008, 09:59 PM

I see. Thinks.

08-22-2008, 09:13 PM	#1
tonytigerking Private First Class Drives: Join Date: May 2008 Posts: 194 iTrader: (0)	Is this normal? Just noticed this today in a long traffic jam. With my a/c on, I noticed that it creates a light vibration when I press the brake down, and I can hear what seems to be motor-like noise along with the engine noise. I've never experienced that with my other cars.
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08-22-2008, 09:35 PM	#2
ML Change for a Nickle? Drives: 2006 M3, Mazda truck Join Date: May 2008 Location: Westfield, MA Posts: 875 iTrader: (1)	Yes, it is normal. The charging system operates only under braking. What you heard was the alternator engaging as you depressed the brake pedal.

08-22-2008, 09:59 PM	#3
tonytigerking Private First Class Drives: Join Date: May 2008 Posts: 194 iTrader: (0)	I see. Thinks.