2021 MY - Passenger and 3rd Brake Lights are out. What's the correct procedure for a full 12V reset?

[rusmo]

They've been out since June 9th and this is the second time it's happened. The last time, the mobile service tech performed a full 12V reset of the car (according to the invoice), and when the car rebooted the lights were working again. He said something along the lines of the car getting "confused" about the state of the lights. /shrug. This "fix" prevented them from having to order new parts and from me having to wait for them to come in.

I think we can all agree it's completely unsafe to drive a car with 2 of 3 brake lights out.

Yesterday, my mobile service appt was pushed back to August 9th due to the parts being delayed. By that time I'll need the car to drive my kids to school and back, so I'm desperate to get this issue resolved - a month without my car for this is unacceptable.

On the 10th, I tried doing the 12V reset myself. Here are the steps I took:
1. With the driver's side door and frunk open, I powered off the car using the touchscreen.
2. Pulled off the top shroud in the frunk and removed the huge HEPA filter.
3. Disconnected the High-Voltage line and heard the audible "thunk" that confirms it was physically disconnected.
4. Disconnected the 12V battery.
5. Waited about 5 mins and then did the above steps in reverse.

Unfortunately this didn't fix the issue this time. Now I'm stuck complaining in the mobile service chat and trying to get a hold of the local service center to acquire a loaner.

I'm left wondering if I missed something in the 12V reset procedure. Does anyone see anything I missed? Anyone else experiencing this issue?

Thanks in advance!

 

[gavinli2007123]

So ya did almost everything correctly. except, you should disconnect the 12v battery before the main hv battery. I'm pretty sure the car throws a bunch of error codes if you disconnect the hv pack first. Also, you can disconnect the pack from one of 2 spots. One of them is the chonky connector under the back seat (The one that goes into the pent house), or you can also disconnect the firemans safety loop under the hood. its on the passenger side of the hood (Its bright orange). Dont cut it, just disconnect the connector that is near it. (Its a small connector.)