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2018 Model 3 Resistive Cabin Heater not working while driving

So my heater finally got fixed. After waiting forever for the part, my car came up with a warning that 'Car may not restart; schedule service'. Tesla responded that it was due to the PTC heater faulting, and that if affects the high voltage loop. Sure enough, next morning, car won't go into gear, lots of messages coming up about electrical system shutting down. Schedule a tow for the Monday. Next day, go to empty out my car and it's completely dead. App won't connect, doors are locked, key card doesn't work. Go buy a 12V from Cdn Tire ($150) and pop the frunk using the cables in the tow port, replace the battery and can open the car & empty out. Install the tow hook in the frunk before locking up again. Sure enough, the next morning, the new 12V is completely dead. Tow it Tesla ($400), and two weeks later get a message it's fixed. Text (because there's no one to call) to ask if the 12V from Cdn Tire is OK and they say it looks fine. Go to pick up the next morning, and there's a 'Schedule service to replace low voltage battery' message on the screen. Go back in to 'service' where I'm told they are too busy to fix and I should take the battery back to Cdn Tire and replace under warranty. So apparently I'm replacing the 12V again this weekend, myself :rolleyes: Unbelievably disappointed in Tesla service. Because nothing was under warranty, I'm stuck without a car without any idea when the part may come in. Had the part come in earlier (in the months that I've had no heat), I could have saved myself over $500 in tow/battery, and having to borrow cars for two weeks when the car became inoperable. So if you're heater goes, get on the list for a new one, because you may think you just have no heat, but eventually your car will die. I did look for an aftermarket/used part and couldn't find one.
 
So my heater finally got fixed. After waiting forever for the part, my car came up with a warning that 'Car may not restart; schedule service'. Tesla responded that it was due to the PTC heater faulting, and that if affects the high voltage loop. Sure enough, next morning, car won't go into gear, lots of messages coming up about electrical system shutting down. Schedule a tow for the Monday. Next day, go to empty out my car and it's completely dead. App won't connect, doors are locked, key card doesn't work. Go buy a 12V from Cdn Tire ($150) and pop the frunk using the cables in the tow port, replace the battery and can open the car & empty out. Install the tow hook in the frunk before locking up again. Sure enough, the next morning, the new 12V is completely dead. Tow it Tesla ($400), and two weeks later get a message it's fixed. Text (because there's no one to call) to ask if the 12V from Cdn Tire is OK and they say it looks fine. Go to pick up the next morning, and there's a 'Schedule service to replace low voltage battery' message on the screen. Go back in to 'service' where I'm told they are too busy to fix and I should take the battery back to Cdn Tire and replace under warranty. So apparently I'm replacing the 12V again this weekend, myself :rolleyes: Unbelievably disappointed in Tesla service. Because nothing was under warranty, I'm stuck without a car without any idea when the part may come in. Had the part come in earlier (in the months that I've had no heat), I could have saved myself over $500 in tow/battery, and having to borrow cars for two weeks when the car became inoperable. So if you're heater goes, get on the list for a new one, because you may think you just have no heat, but eventually your car will die. I did look for an aftermarket/used part and couldn't find one.
Wow, what a saga. Do they have any idea what killed the new 12V battery overnight?
 
So my heater finally got fixed. After waiting forever for the part, my car came up with a warning that 'Car may not restart; schedule service'. Tesla responded that it was due to the PTC heater faulting, and that if affects the high voltage loop. Sure enough, next morning, car won't go into gear, lots of messages coming up about electrical system shutting down. Schedule a tow for the Monday. Next day, go to empty out my car and it's completely dead. App won't connect, doors are locked, key card doesn't work. Go buy a 12V from Cdn Tire ($150) and pop the frunk using the cables in the tow port, replace the battery and can open the car & empty out. Install the tow hook in the frunk before locking up again. Sure enough, the next morning, the new 12V is completely dead. Tow it Tesla ($400), and two weeks later get a message it's fixed. Text (because there's no one to call) to ask if the 12V from Cdn Tire is OK and they say it looks fine. Go to pick up the next morning, and there's a 'Schedule service to replace low voltage battery' message on the screen. Go back in to 'service' where I'm told they are too busy to fix and I should take the battery back to Cdn Tire and replace under warranty. So apparently I'm replacing the 12V again this weekend, myself :rolleyes: Unbelievably disappointed in Tesla service. Because nothing was under warranty, I'm stuck without a car without any idea when the part may come in. Had the part come in earlier (in the months that I've had no heat), I could have saved myself over $500 in tow/battery, and having to borrow cars for two weeks when the car became inoperable. So if you're heater goes, get on the list for a new one, because you may think you just have no heat, but eventually your car will die. I did look for an aftermarket/used part and couldn't find one.
That's awful service and design on Tesla's part. Sorry you had to go through all that.
 
Just the PTC heater faulting, I guess?

I had a fault with the PTC recently as well (2018 LR RWD), but I am still in warranty so it was no cost. In my case the car did not shut down, I would only get heat for a minute or so and then it would stop for the rest of the drive.

From what I understand the PTC heater is attached to the high voltage system. If a fault is found in the PTC that suggests a short/serious fault the car immediately disconnects the high voltage system, thus the charging of the 12V battery stops (this is similar to what happens when the pyro fuse pops).

Once the computers run the battery down that is it, the car is "dead" and needs to be boosted.

Probably this is a better design choice than leaving 400V going into a possible short circuit in the PTC heater, which I am sure would be quite exciting, especially since it is located under the dash in the passenger compartment.

In my case although Tesla didn't have a PTC in stock they wanted me to bring the car in immediately due to the risk of a shutdown. I was given a Tesla loaner until the work was done. I felt it was handled well.

I do notice there are 2 revisions of the PTC, the latest being a -I version, which is what was installed as a replacement, so perhaps this one is improved.
 

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