All 3 Brake Lights Stay Illuminated

[thatslowkey]

Hello! I just purchased a used 2012 BMW 535i Xdrive about a month ago. So far I'm loving it but recently I've discovered an issue where once I start the vehicle, the 3 rear tail lights stay illuminated as if my foot is on the brake pedal & do not turn off until I lock the car.
I'm quite new to BMW & would like some assistance as where I should start looking to diagnose the issue! Any help is appreciated, thank you in advanced

Here's a video just in case that will help at all https://www.youtube.com/watch?v=T_fveO0t4JA

- Luis

[White94RX]

Most likely is the stop light switch.

Come to think of it, do these cars still use a stop light switch at the top of the brake pedal? The last time I replaced or adjusted one was on an E65

[thatslowkey]

Yea I believe the f10’s still use that pesky brake light switch at the top of the pedal assembly.
I’ll pull the connector later on this week and see if it makes any changes.

[White94RX]

It also may just need to be adjusted. Just push the brake pedal, push the switch in its holder towards the pedal, then release the pedal. It will push the sensor to the exact adjustment needed. It’s a hall-effect sensor and just senses the metal of the pedal. Not actually pressing a micro switch.


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[thatslowkey]

AhhHhHh ok once I pull the connector on the stop light switch to see if its the source of the issue, I’ll give the adjustment a shot after.
Thank you again for the assistance, its much appreciated.

[White94RX]

Any update?


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[thatslowkey]

Unfortunately no update yet, I work a lot so I haven’t had too much free time lately but I’ll jump into it today and give a crack at checking the stop light switch 👍🏽

[thatslowkey]

Here’s an update on my attempt to rule out a bad stop light switch as the culprit

https://youtu.be/mk7U42CVW7w

[White94RX]

Watched the video. Thanks for the shout out. My only question is if your test by disconnecting the switch was valid or not. Like does the FRM or whatever module turn on the brake lights as a default when there’s no connection to the switch? BMW does things like that sometimes. We’ve always been told when a passenger seat mat sensor is bad, if there’s an accident, the passenger airbag will be fired as a default since it doesn’t know if the seat is occupied or not. For safety.

Backing up a little, do you have ISTA, or any other diagnostic software that will let you read faults from all the control units? Not a cheap OBD scanner. If you plan on keeping the car awhile, and doing your own diagnostics and repairs, it’s a worthwhile investment. ISTA is dealer level software and will let you do what we do, including coding and programming.


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[thatslowkey]

I’m actually in the process of downloading ISTA as we speak, hoping to venture a bit further toward finding exactly where the issue lies.

I have a feeling the FRM may not be receiving signal or there is a lack of connection to the brake light switch.

I’m going to try to utilize ISTA to view any signs of fault in the module.
This will be my first time using ISTA but as you said it’s a great investment to have in the long run.

[White94RX]

Any update? Got ISTA to work?

There are status requests in ISTA that you can look at and it will tell you directly if things like the stop light switch is activated, or if maybe the DSC pressure sensor senses brake pedal pressure and is turning on the lights.


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[ny2001740]

hello i know i have a different model car e38 2001 bmw 740 il but i have the same problem .i dont know if it is from i just changed the ign swtch but 4 days later i disconnected the battery and touched both cables together to clear whatever codes were on the car...i saw it on one one of these forumns i hope i didnt mess anything up or does it have to be programmed by someone...oh and i just put a new brake light switch on it and nothing happened...i have aftermarket lights in the rear for over 10 years never had this problem..thank you..for any help..

[thatslowkey]

UPDATE: Alright boys, apologies for my long absence. Due to the pandemic & work I’ve been extremely busy and distracted but, we have discovered the culprit to my brake light issue!!!
I started by replacing the stoplight switch with a brand new oem unit & the problem persisted.
So a buddy of mine diagnosed the vehicle using ISTA ( thank you @White94RX ) & it turns out my FRM (Footwell Module) is indeed faulty.
We can see the new stoplight switch is functioning normally however the FRM seems to be showing that it is receiving a constant signal.

[thatslowkey]

UPDATE #2 (Finally Resolved) we resolved the issue and confirmed that the FRM was damaged (most likely from the dealership employees jump starting the vehicle after sitting for so long) I purchased a used FRMIII from eBay which showed up today! I took the new FRMIII 7 & vehicle to a well known shop in Brooklyn (@BMCODINGNYC on Instagram) to have the module installed & programmed. Roughly 30 mins later the FRMIII was installed & brake lights function properly once again!!!! I'm happy as can be

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hello i know i have a different model car e38 2001 bmw 740 il but i have the same problem .i dont know if it is from i just changed the ign swtch but 4 days later i disconnected the battery and touched both cables together to clear whatever codes were on the car...i saw it on one one of these forumns i hope i didnt mess anything up or does it have to be programmed by someone...oh and i just put a new brake light switch on it and nothing happened...i have aftermarket lights in the rear for over 10 years never had this problem..thank you..for any help..

Honestly it sounds like something definitely short circuited there... I would begin checking all the fuses in the glove box first & rear cargo cabin to be on the safe side. If all checks out I would bring to someone familiar with BMW ISTA P or similar software to run a diagnostic on the vehicle & check the conditions of thee associated modules relating to your issue. My recommendation seeing you are from NY is @BMCODINGNYC on instagram. They're right in red hook BK & do great work!