2014 Tesla Model S P84D 12V battery dead

[GregMunch]

2014 Tesla Model S P85D 12V battery has gone dead. Car dead. This car is unsupported by Tesla.
Here's my story: Drove through a medium sized maybe 8" deep rain puddle. A few seconds later as I was driving i received a warning on the screen "Immediate Service", "12 volt battery". Drove 5 miles more to home and parked. Next morning 12 volt battery dead. Replaced battery, but got additional warnings, "reduced power", "car may not start", also heater and AC didn't come on. I read through threads on this form about dc to dc converter having bad fuses, so thats were I started. I retrieved the converter only after 6 hours of knuckle slicing agony to find out mine doesn't require fuses. this 2014 is a late manufacture date and is a third generation type. I guess the DC to DC converter could still be bad, but I don't want to start just swapping parts. Is there a way to bench test this unit? Am I looking in the wrong direction?
I am assuming the main fuse and conductors in the battery are good because I was not left stranded on the road
Any input is appreciated.
Thank you!

 

[Tam]

...12V battery has gone dead...

You didn't say after swapping the 12V, does your car charge normally?

If not, the cause might not be the 12V but the main battery.

Main battery fails -> AC, Heater, 12V.. fail.

So I would fix the main battery first!

 

[aerodyne]

Check the 12v grounding!

 

[MP3Mike]

I assume that water go into some electrical connection when you went through the puddle and as such it fails the HV isolation test now. So the car won't "turn-on" the HV battery.

You will likely need someone to help identify the issue. Either Tesla or a hacker. I'm assuming it is a salvage vehicle and that is why you say it is unsupported. But do know that Tesla will work on salvage cars now, but for them to work on the HV system you have to pay for, and pass, an HV inspection first. (I think it costs around $500 for the inspection. Note: They will disable Supercharging when they do the inspection.)

 

[GregMunch]

You didn't say after swapping the 12V, does your car charge normally?

If not, the cause might not be the 12V but the main battery.

Main battery fails -> AC, Heater, 12V.. fail.

So I would fix the main battery first!

No change, still does not charge, same symptoms as before.

 

[GregMunch]

I assume that water go into some electrical connection when you went through the puddle and as such it fails the HV isolation test now. So the car won't "turn-on" the HV battery.

You will likely need someone to help identify the issue. Either Tesla or a hacker. I'm assuming it is a salvage vehicle and that is why you say it is unsupported. But do know that Tesla will work on salvage cars now, but for them to work on the HV system you have to pay for, and pass, an HV inspection first. (I think it costs around $500 for the inspection. Note: They will disable Supercharging when they do the inspection.)

I am in the business, so my hope is someone with Tesla knowledge can point me in the right direction. With out the diagnostic software it's a guessing game. I will take it to Tesla as a last resort. Or see if Tesla will bench test my converter.

 

[PWlakewood]

I am in the business, so my hope is someone with Tesla knowledge can point me in the right direction. With out the diagnostic software it's a guessing game. I will take it to Tesla as a last resort. Or see if Tesla will bench test my converter.

So is it salvaged?

 

[GregMunch]

So is it salvaged?

yes