Tesla Model 3 Dead 12v Battery Replacement Experience
My girlfriend this morning attempted to borrow my 2021 Tesla Model 3, but it failed to respond to her keyfob. When she opened the door, the screen inside stayed off. When she tried to close the door, it failed to latch and stayed slightly ajar. All of these factors indicating a dead 12 volt battery.
When I had a moment midday during work, I started the process to jump the Tesla. Searching online, I found out the 12v battery is located under a cover in the frunk. But because my battery was dead, I would need to manually open the frunk. This action was not intuitive. You needed to pop open a circular clip cover located up front, below the frunk. Once opened, you can pull out two wires, a positive and a negative. When charged, this should be enough for the frunk to pop open.
When I attempted this, nothing happened. I was quite confused because I thought this would work. Doing more research, it turns out the frunk, as a safety mechanism, will not open in this manner if there is ANY juice left in the 12v battery. This handles the case in which a thief would attempt to access the frunk while the car is in a healthly state.
Learning this, it implied my 12v battery still had some juice. The Tesla app on my phone seemed unresponse in previous attempts to remotely control the car. I tried again and now I could release the first latch of the frunk with the standard unlock button within the app. But the secondary safety latch remained in place, keeping the frunk locked, but partially open. Open enough to have yoru fingers be able to go inside.
After many failures of trying to manually unlock the secondary latch, I tried the app again. Going into an alternative controls menu and unlocking the frunk did the trick. Very frustrating how random this felt. Removing the cover and jumping the 12v battery was then quite easy in comparison to the previous steps.
It is worth noting that before I attempted to jump the car, I checked the Tesla app for mobile repair. The app said they could come to my house and replace my battery, but earliest appointment would be 2 days away. I needed my Tesla fixed ASAP.
I called the local dealership, and they said they would be able to squeeze me in before end of day. I jumped in the Tesla and began to head down the road, quickly noticing that the brakes were quite stiff. The car was picking up speed more slowly than usual. And the regenerative braking was not working at all. The car would roll much like a normal non-regenerative car would. The brake experience was similar to the experience of when my old Toyota Tacoma truck had a faulty brake line; giving 10% of the brake power it did when in working order.
I debated scratching the in person drop off all together since the brakes felt unreliable. Exiting my neighborhood, I performed some testing to see if the brakes still functioned despite the increased pedal resistence. Pushing with notable force, I was able to slow to a stop, but not in an immediate manner. Abrupt stops would be a problem (just like my Tacoma). Keeping this in mind, I went out onto the public road.
At this time people were commuting home from work. I gave 3+ car lengths of space between me and the next car. Getting onto the highway was similar to getting onto a terrifying rollercoaster. Speeding down the onramp was like feeling the clicks of climbing up the huge hill that starts the roller coaster, knowing whatever came next was unstoppable.
I stayed in the right hand land going 55mph. At the exit, it was luckily a straightaway offramp rather than a 360 degree turn. Still, I let off on the gas pedal very early and rolled to a stop, using the brakes to hold me in place once halted. People behind me circled around, causing no issue.
Eventually I arrived at the dealership. The receptionist remembered who I was on the phone and was able to expedite the process. She was exceedingl helpful. The replacement itself took only 15 minutes!
Jumping and replacing my dead 12v battery was a negative experience, with the silver lining being the speedy service. In the future, the better option would be to wait for the mobile repair appointment and have them do all the work!
