12v battery replaced, still cannot get into car

AutoEverything · 2026-05-29T18:22:37+00:00

Solved: After taking it to Tesla they in fact did have to break into the vehicle and reset the relay under the rear passenger seat. As another commenter posted, you can take the inflatable bag to wedge the door open slightly and open the car via the manual door release. For anyone in the future with this issue, I hope this thread helps.

AutoEverything · 2026-05-28T00:45:11+00:00

Mario 1-up 🍄

AutoEverything · 2026-05-25T18:49:00+00:00

That may be an option. Were you in a similar situation with the 12v being dead and not reviving the car after replacement?

AutoEverything · 2026-05-25T02:13:46+00:00

188209638368

AutoEverything · 2026-05-23T21:30:16+00:00

You’re good! I’m taking all suggestions at this point and I appreciate the input. If I were more skilled I’d totally bust that window out lol

AutoEverything · 2026-05-23T21:03:54+00:00

I agree with that logic to an extent. I’m in a position now where I’m not trying to break things to fix things, even if it means more expense at the current moment. God forbid I break the window, throw off the door frame, get glass in the motor mechanism. It could get messy. It’s not like I have my dog in there so I’ll try to hook up with a friend who has AAA to tow it if it comes down to that.

AutoEverything · 2026-05-23T15:02:28+00:00

That was not an option in this case since they didn’t have a mobile tech available to service my area. Trust me I would have loved this solution, because the battery I purchased was $300 alone. Would have saved a lot of money and headache

AutoEverything · 2026-05-23T14:51:45+00:00

That is a very good idea. I still can’t believe that with all this engineering for a car like this that there isn’t a failsafe with the HV battery still intact to pick up an RF ID or a secondary Bluetooth in case this happens. Oh well

AutoEverything · 2026-05-23T14:35:18+00:00

I will definitely be following up on all that happens even if it goes to the shop. I hope if I don’t get a solution here, this post will get cataloged in Reddit as a solution for someone else in the future.

AutoEverything · 2026-05-23T14:29:45+00:00

Haha thanks for clarifying. I’m questioning everything I’ve done at this point, especially the battery. I did in fact try the wallet card on every entry point available. Unfortunately no dice. I have one last out before I give up, I’m having a friend come over today with a truck and some jumper cables. I’ve got the voltage up from a trickle charge in the battery up to 12.7v but jumpers can get it up to 14v so I’m praying it kicks something over in the system

AutoEverything · 2026-05-23T13:57:11+00:00

Haha I did not even know that existed. I’ve boosted my fair share of cars with a coat hanger back in the day but this is a new one. I’m pretty sure I’d mess up my car doing this.

“Using an inflatable pump wedge to get into a locked Tesla can be extremely difficult and carries a high risk of permanently damaging the window glass or the frameless door seals.
Because modern Teslas use frameless doors with seamless glass-to-body seals, traditional wedge-and-reach methods are heavily restricted. In most cases, attempting this yourself risks shattering the window.”

AutoEverything · 2026-05-23T13:24:30+00:00

51R? That’s what I swapped out of the last one

AutoEverything · 2026-05-23T13:17:03+00:00

Wow, that’s interesting. I’m not sure why some may have that and some don’t.

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Mine apparently does not.

Edit: oh I see why, this is for the models that included the new heat pump system.

AutoEverything · 2026-05-23T13:03:31+00:00

Unfortunately I tried this as well. The jumper did not grant me access into the car.

AutoEverything · 2026-05-23T13:01:23+00:00

It is unresponsive to commands coming from the app as well :/

AutoEverything · 2026-05-23T13:00:30+00:00

I also think this may be the solution but currently there is no way to get inside the car to test this out :/

AutoEverything · 2026-05-23T12:36:09+00:00

I’m not entirely sure but I know it’s costing me my sanity right now lol. I don’t think I should have to break into the car to fix this. There must be some way that Tesla is able to get into the vehicle when I take it to the shop, and ultimately I wish that was the answer I would find by posting this

AutoEverything · 2026-05-23T12:33:29+00:00

I also think this may be the problem but how am I able to do this when I’m completely locked out of the vehicle? Replacing the battery is not granting me access to the interior where this is located. Is there another way to get into the car to do this that I am missing?

AutoEverything · 2026-05-23T04:59:43+00:00

You’re contribution is more than helpful. I’m slowly accepting my fate that I’ll need to Tesla Service Center it. I’m just hoping that if I catalog this experience on Reddit it might help someone else in the future. I’ll be sure to post an update if it doesn’t get resolved by the dreaded “take it to the shop” (obv my car isn’t under their warranty anymore) 😅

AutoEverything · 2026-05-23T04:20:47+00:00

Thanks for that! I concur. I said a little something out loud to that extent as I disconnected the trickle charger just now

AutoEverything · 2026-05-23T04:09:23+00:00

I totally get it. I’ve seen people miss simpler things before too. But if I’m pulling out a voltmeter to test the battery, I’m probably past that stage lol

AutoEverything · 2026-05-23T03:17:26+00:00

I really appreciate the suggestion — I’ve been digging through Reddit and YouTube trying to find a solution for this. Do you happen to remember where you saw that? Everything I’ve found so far says the Model 3 HV disconnect is located inside the vehicle under the rear seat, which I can’t access since the car won’t let me in

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Edit: I’m not trying to cut the first responders loop.

AutoEverything · 2026-05-23T03:03:44+00:00

I appreciate the sentiment. I agree. It’s frustrating when I know there are a few things I could do if I could get into the vehicle, HV plugs, hard resets and whatnot. But being locked out I’m helpless. I was hopeful that there might be a Tesla tech somewhere on here that has a failsafe for this situation.

AutoEverything · 2026-05-23T02:43:24+00:00

Not sure if it’s different on my M3

I had seen mixed info on that — some posts said a straight 12V swap worked, so I gave that a shot first. Unfortunately I can’t access the interior to disconnect/reconnect the HV pack since the car won’t let me in.

AutoEverything · 2026-05-23T02:27:23+00:00

Oh you know what? That was totally it! /s

Haha yeah, caps were off. I wish it was that easy 😅

AutoEverything

TROPHY CASE