Brake lights don't light up until ignition is on

thatg20guy · 07-09-2016, 01:15 AM

Not sure if this has been asked previously (a search on the forums yielded no such result) but I was just curious if the brake lights light up when the brake pedal is depressed but the ignition is off. On my F30, it seems as if the brake lights are not illuminated until the ignition is switched on.

Does anyone else have similar experiences? Not an issues for me, just curious.

Katin · 07-09-2016, 09:00 AM

Yes. Garage door buttons also.

goj · 07-09-2016, 10:28 AM

So you don't drain the battery.

AndDown · 07-09-2016, 10:36 AM

Isn't this normal for most ( if not all) cars, ignition must be on first.

Billfitz · 07-09-2016, 11:14 AM

Quote:

Originally Posted by AndDown

Isn't this normal for most ( if not all) cars, ignition must be on first.

Most cars don't have power management systems, so their brake lights will work when the ignition is off.

AndDown · 07-09-2016, 11:31 AM

Quote:

Originally Posted by Billfitz

Most cars don't have power management systems, so their brake lights will work when the ignition is off.

Interesting to know - I've had BMW's since the 70's so thought this was common of most cars.

Billfitz · 07-09-2016, 12:18 PM

Quote:

Originally Posted by AndDown

Interesting to know - I've had BMW's since the 70's so thought this was common of most cars.

My BMW is the first car I've owned where the brake lights didn't come on with the ignition off, going back to 1967. The likely reason for the BMW arrangement is so a faulty brake light switch won't cause them to kill your battery. I seem to recall somewhere in the dim past that I had a car where the brake lights wouldn't go off due to a bad switch. Probably my '63 Impala.

hsk1610 · 07-09-2016, 02:36 PM

Yeah noticed this few days ago when I replaced the rear brake lights with leds and was testing to make sure they were working.

thatg20guy · 07-10-2016, 12:04 AM

Thanks for the replies everyone! It was just something that's been nagging me for the past year. I figured it was something to do with not draining the battery, but I also wondered if my car was being weird. Now I know!

tex2670 · 07-10-2016, 06:43 AM

Quote:

Originally Posted by AndDown

Isn't this normal for most ( if not all) cars, ignition must be on first.

It is not normal for most cars. I have never had a car that the brake lights didn't work when the car was off.

07-09-2016, 01:15 AM	#1
thatg20guy Private First Class 70 Rep 173 Posts Drives: 2021 M340i Join Date: Jun 2015 Location: Chicago, IL iTrader: (0) Garage List 2021 BMW M340i xDrive [0.00]	Brake lights don't light up until ignition is on Not sure if this has been asked previously (a search on the forums yielded no such result) but I was just curious if the brake lights light up when the brake pedal is depressed but the ignition is off. On my F30, it seems as if the brake lights are not illuminated until the ignition is switched on. Does anyone else have similar experiences? Not an issues for me, just curious.
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07-09-2016, 09:00 AM	#2
Katin Second Lieutenant 134 Rep 291 Posts Drives: 2015 328i XDrive Join Date: Mar 2016 Location: Nowhere good iTrader: (0)	Yes. Garage door buttons also.
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07-09-2016, 10:28 AM	#3
goj Brigadier General 2255 Rep 3,622 Posts Drives: 2016 EBII 340i 6-MT Join Date: Aug 2015 Location: Bay Area, CA iTrader: (0)	So you don't drain the battery. __________________ BMW CCA Member #516012 2016 340i, Estoril Blue, Manual Transmission, MPE, MPBBK, HRE FF04 Instagram: @brandons340i
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07-09-2016, 10:36 AM	#4
AndDown Just Copacetic! 178 Rep 616 Posts Drives: 2019 F22 230i MSport Join Date: Aug 2012 Location: Redlands, CA iTrader: (0)	Isn't this normal for most ( if not all) cars, ignition must be on first.
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07-09-2016, 02:36 PM	#8
hsk1610 Lieutenant 108 Rep 524 Posts Drives: 2013 328i xDrive Join Date: Sep 2013 Location: Chicago, IL iTrader: (0)	Yeah noticed this few days ago when I replaced the rear brake lights with leds and was testing to make sure they were working.
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07-10-2016, 12:04 AM	#9
thatg20guy Private First Class 70 Rep 173 Posts Drives: 2021 M340i Join Date: Jun 2015 Location: Chicago, IL iTrader: (0) Garage List 2021 BMW M340i xDrive [0.00]	Thanks for the replies everyone! It was just something that's been nagging me for the past year. I figured it was something to do with not draining the battery, but I also wondered if my car was being weird. Now I know!
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