Heated mirror and rear defroster issue

[MaxxGray]

I have a 2018 model 3- dual motor extended range, which is just out of warranty. I noticed that my rear defroster doesn't seem to be working. I'd noted this before, but just thought that it was lousy, and didn't think much of it. Also notable, is that shortly after I purchased the car, I did have tint put on. I do not see a disruption in the connection or wires on the back window.
While I was researching this issue, I also noticed that people are reporting that they have heated side mirrors. If I have these, they also have never worked.

I'm looking to see if anyone else has had this problem or if anyone knows of a common pathway to troubleshoot why both my rear defroster and heated mirrors are non functional. If this was any other type of car, I would suspect a fuse problem, but I'm told that the model 3 does not have fuses.
If the only solution is to replace the rear window and have it retained at my own expense, I'm likely just going to live with it for the life of the vehicle.

 

[FastEddieB]

I was about to post about the same issue.

On my 2022 M3LR, yesterday I had condensation on the rear window. I drove at least 20 minutes with the rear defroster on and never saw the heating element lines doing their jobs. It took longer than that for the condensation to finally dissipate uniformly, much as it would without rear defrost on. By comparison, in my other cars you can see the heating element lines dissipating the condensation in a mile or two.

No tint at this time. Time for a service call?

 

[Randy-12]

I was about to post about the same issue.

On my 2022 M3LR, yesterday I had condensation on the rear window. I drove at least 20 minutes with the rear defroster on and never saw the heating element lines doing their jobs. It took longer than that for the condensation to finally dissipate uniformly, much as it would without rear defrost on. By comparison, in my other cars you can see the heating element lines dissipating the condensation in a mile or two.

No tint at this time. Time for a service call?

When I had my car in service earlier this month for an unrelated issue they kept the car overnight and I picked it up first thing in the morning.
There was dew on the car and I turned on the rear defrost. Went inside the building to return the loaner key card and came back out.

Nothing on the rear window, not a line no signal that it was in fact working, still 100% full dew.
Went back inside and asked the tech why, as I said all previous cars I've had it was almost instantly apparent that it was working.
He said to give it time, that it was not quick. About 10 minutes later window was clear.

So it was "within spec" as they say.