Executive summary: If you drive a Model S, X or 3 and the brake lights won't turn off, take this very seriously, because you might be in for a major inconvenience, or even long term battery damage.
My Model 3 was working great (except for the defective turn signal stalk and intermittently inoperable HVAC blower) for the first 11 days of ownership. Then on Halloween someone at work came by my desk to say I left my headlights on. Odd... That's not really possible. Upon inspection I found that everything was on and the doors were not locked. I shut off everything individually and locked the doors with the key card, but the center display was still on, and so were the brake lights. I called Tesla and they scheduled a mobile tech to check on the car the next day. I drove home carefully that night knowing that stuck brake lights are essentially the same as having no brake lights. I resolved to drive my beater Prius (11 years old, 191k miles, zero issues ever). While I was at work the next day the tech went to my house and found a faulty brake switch, which apparently notifies the car when the brake pedal is being pressed, and ordered a new one, which takes about a week to arrive. He said he was able to get the brake lights to turn off, but after driving the car for a few minutes they came back on. Instead of doing the reset maneuver again, he left my car sitting with the headlights and heat on when he left my house. I returned home from work at 10pm to find the battery state-of-charge (SoC) getting low. Annoying, but fine. I'll just plug it in. But when the brake pedal is pressed, the charge port door cannot be opened. That means I can't charge the battery. I tried to do a full "Power Off" but there again, pressing the brake wakes the car, so it would not power off. Resetting the computer didn't help. So I turned off the heat, seat heaters, lights and dimmed the display to 0% hoping the 49% SoC would get the car through the next week of sitting in the garage waiting for the repair. It did not. With the car fully powered up the SoC dropped by about 12 points per day, so by Sunday I was in a panic when it was in single digits. I spent a lot of time reading these forums and watching YouTube videos trying to find some way to get the thing to take a charge or power off. Unfortunately everything I found was negated by pressing the brake pedal. I was desperate because I know that when the battery hits 0% SoC and goes into emergency shutdown mode, the parking brake can't be disengaged so towing is difficult. The doors can't easily be opened. The 12v battery will drain, which will kill the lead acid cells. And leaving a lithium ion battery fully discharged for days on end is bad for its longevity. All this because of a little switch that I imagine is a pretty simple $10 part. I wonder if this potential failure was ever considered during the design of the car.
I should mention that I called Tesla at least once per day every day since this happened and they did nothing to help me. No tow truck, no emergency repair, no loaner, no calls back from my voice mails or from the people who said they would. On Saturday I thought I made progress when someone agreed to have the car towed to the nearest service center. He said he'd call me right back because he couldn't call the towing company while I was on the other line, and never did. No tow truck ever arrived. I never heard from him again. I've learned that "I'll call you back" is code for "My shift ended ten minutes ago and I'm outta here." (Do I sound like a jerk? I only say this because it has happened so many times over the years.)
So on Sunday I was desperate to get the car to either power off or take a charge before it hit 0% SoC. I figured out how to access the 12v battery (easy) and disconnected the positive lead. Weirdly, nothing happened except for a fresh error on the display. I left it this way for a couple of hours but nothing changed. I pulled the manual charge port door release cable inside the trunk and more errors appeared on the display, but the little door didn't open. I then pried open the door with a special plastic tool (a pen) and winced as its little motor kept trying to close it against my grip. I plugged in a my UMC cable and the T logo turned blue for a second, then red, then I heard a very alarming CLUNK! come from the front of the car and everything went dark and quiet. Not quite the success I had hoped for, but at least it seemed to be fully powered off at 6% SoC. With the UMC still connected (I couldn't disconnect it now) I reconnected the positive cable to the 12v battery. To my amazement the car hummed to life and the computer booted up without any errors or complaints. There was a loud hum for about 2 minutes, but that stopped and the battery was charging! The brake lights were also off. I charged it to 90% and am confident it can survive until the repair guy returns, especially since it's still plugged in.
Yes, that's long-winded, but I'm writing this more for myself than for anyone else. I was so annoyed and frustrated, then relieved that I had to tell someone who would understand. Thanks, Tesla community!
Lessons learned
My Model 3 was working great (except for the defective turn signal stalk and intermittently inoperable HVAC blower) for the first 11 days of ownership. Then on Halloween someone at work came by my desk to say I left my headlights on. Odd... That's not really possible. Upon inspection I found that everything was on and the doors were not locked. I shut off everything individually and locked the doors with the key card, but the center display was still on, and so were the brake lights. I called Tesla and they scheduled a mobile tech to check on the car the next day. I drove home carefully that night knowing that stuck brake lights are essentially the same as having no brake lights. I resolved to drive my beater Prius (11 years old, 191k miles, zero issues ever). While I was at work the next day the tech went to my house and found a faulty brake switch, which apparently notifies the car when the brake pedal is being pressed, and ordered a new one, which takes about a week to arrive. He said he was able to get the brake lights to turn off, but after driving the car for a few minutes they came back on. Instead of doing the reset maneuver again, he left my car sitting with the headlights and heat on when he left my house. I returned home from work at 10pm to find the battery state-of-charge (SoC) getting low. Annoying, but fine. I'll just plug it in. But when the brake pedal is pressed, the charge port door cannot be opened. That means I can't charge the battery. I tried to do a full "Power Off" but there again, pressing the brake wakes the car, so it would not power off. Resetting the computer didn't help. So I turned off the heat, seat heaters, lights and dimmed the display to 0% hoping the 49% SoC would get the car through the next week of sitting in the garage waiting for the repair. It did not. With the car fully powered up the SoC dropped by about 12 points per day, so by Sunday I was in a panic when it was in single digits. I spent a lot of time reading these forums and watching YouTube videos trying to find some way to get the thing to take a charge or power off. Unfortunately everything I found was negated by pressing the brake pedal. I was desperate because I know that when the battery hits 0% SoC and goes into emergency shutdown mode, the parking brake can't be disengaged so towing is difficult. The doors can't easily be opened. The 12v battery will drain, which will kill the lead acid cells. And leaving a lithium ion battery fully discharged for days on end is bad for its longevity. All this because of a little switch that I imagine is a pretty simple $10 part. I wonder if this potential failure was ever considered during the design of the car.
I should mention that I called Tesla at least once per day every day since this happened and they did nothing to help me. No tow truck, no emergency repair, no loaner, no calls back from my voice mails or from the people who said they would. On Saturday I thought I made progress when someone agreed to have the car towed to the nearest service center. He said he'd call me right back because he couldn't call the towing company while I was on the other line, and never did. No tow truck ever arrived. I never heard from him again. I've learned that "I'll call you back" is code for "My shift ended ten minutes ago and I'm outta here." (Do I sound like a jerk? I only say this because it has happened so many times over the years.)
So on Sunday I was desperate to get the car to either power off or take a charge before it hit 0% SoC. I figured out how to access the 12v battery (easy) and disconnected the positive lead. Weirdly, nothing happened except for a fresh error on the display. I left it this way for a couple of hours but nothing changed. I pulled the manual charge port door release cable inside the trunk and more errors appeared on the display, but the little door didn't open. I then pried open the door with a special plastic tool (a pen) and winced as its little motor kept trying to close it against my grip. I plugged in a my UMC cable and the T logo turned blue for a second, then red, then I heard a very alarming CLUNK! come from the front of the car and everything went dark and quiet. Not quite the success I had hoped for, but at least it seemed to be fully powered off at 6% SoC. With the UMC still connected (I couldn't disconnect it now) I reconnected the positive cable to the 12v battery. To my amazement the car hummed to life and the computer booted up without any errors or complaints. There was a loud hum for about 2 minutes, but that stopped and the battery was charging! The brake lights were also off. I charged it to 90% and am confident it can survive until the repair guy returns, especially since it's still plugged in.
Yes, that's long-winded, but I'm writing this more for myself than for anyone else. I was so annoyed and frustrated, then relieved that I had to tell someone who would understand. Thanks, Tesla community!
Lessons learned
- Stuck brake lights might indicate a really serious problem in a Tesla, namely, you can't power it down or charge it.
- When talking to someone in tech support or customer service, get his/her callback number! If someone says he'll call you back, he probably won't.
- If you're stuck troubleshooting your own car when it's in a severely uncooperative state, disconnect the 12v battery in the frunk and connect a charge cable to cause the car to freak out and power down. Reconnect the 12v battery and it'll boot up. This might break your car. I don't actually know for sure. Didn't seem to break mine.
