SIGforum
Brake lights backwards?

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/320601935/m/4250055305

September 20, 2023, 09:35 AM
holdem
Brake lights backwards?
Yesterday I am at a four way stop. The car to my right, a black Chevy Malibu, goes straight. Then I turn left and I am now behind this Chevy Malibu.

I see their brake lights are on and I think to myself, "Ugh, another idiot riding the brakes." But over the course of the next mile or so at 45 mph the lights never go off. Until a car pulled out in front of them and they have to slow down and that is when the brake lights go off. As the other car accelerates and we start to resume normal speed, the brake lights come back on. I think to myself, "That was really weird, it's almost like they are wired backwards. The lights are on when no foot is on the brake pedal. But when a foot touches the brake pedal, the lights go off."

I follow this car for over another mile. We make one 90 degree right hand turn. And then at the next intersection, they make a 90 degree right and I make a 90 degree left. And sure enough, the brake lights were always on, except when the car slowed and that is when the lights went off.

Unfortunately, this was a two lane country road, so I could never get next to this car and warn them of their issue. I am assuming some wiring was installed incorrectly? But I would think that connectors would be made so this sort of thing wasn't even possible? How the heck does this happen?
September 20, 2023, 09:46 AM
selogic
CAN it be wired this way ? Absolutely . Especially if it uses a relay . Normally open versus normally closed contacts .
September 20, 2023, 10:42 AM
rizzle
Out of curiosity on my part, did a little searching, but without the year of the Malibu it may not apply. I enjoy automotive electrical problems and actually made a living out of it.
Everything is BCM (Body Control Module) now and each manufacture does it differently.
So to answer your question, Yes, they can work backwards, could be a bad BCM or open/shorted signal connection.
Here is a link to a Malibu forum, Lots of adds in it, It is so nice to be on Sigforum and not have to deal with advertising.
https://www.chevymalibuforum.c...ning-correctly.8519/
September 20, 2023, 11:11 AM
holdem
quote:
Originally posted by rizzle:
but without the year of the Malibu it may not apply.


Looking online, it was most likely 2008-2012, small possibility it was 2012-2016.
September 20, 2023, 11:13 AM
P250UA5
Looks like this from behind?
I recall these having some issues with the LED taillights on the LTZ, could've been something like that causing it.





The Enemy's gate is down.
September 20, 2023, 11:22 AM
rizzle
Here is the TSB (service bulletin) from GM on it.
PDF File:
https://static.nhtsa.gov/odi/t...MC-10126014-9999.pdf
September 20, 2023, 11:42 AM
holdem
quote:
Originally posted by rizzle:
Here is the TSB (service bulletin) from GM on it.


Well all be darned. There it is.
September 20, 2023, 11:52 AM
Johnny 3eagles
Now all you gotta do is drive around town until you find him and give him a copy of the TSB Smile





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