Rear Defroster Issues?

  • SUPPORT THE SITE AND ENJOY A PREMIUM EXPERIENCE!
    Welcome to Tesla Owners Online, four years young! For a low subscription fee, you will receive access to an ad-free version of TOO. We now offer yearly memberships! You can subscribe via this direct link:
    https://teslaownersonline.com/account/upgrades

    SUBSCRIBE TO OUR YOUTUBE CHANNEL!
    Did you know we have a YouTube channel that's all about Tesla? Lots of Tesla information, fun, vlogs, product reviews, and a weekly Tesla Owners Online Podcast as well!

mtdoak

Well-known member
Joined
Aug 1, 2017
Messages
220
Location
Allentown, PA
Tesla Owner
Model 3
Country
Country
#1
I'm very curious about something.

Last Night, we got a little bit of snow. Not a ton mind you, but maybe 1/8th of an inch. A dusting. I work from home and go out and get coffee most mornings. So, I preheat the car for a few minutes while I walk my dog, come and sit down inside the car. The snowflake is on (as expected). I blast the heat in defrost setting, my front window in clear quickly.

On my way back from the coffee shop, I notice my rear window isn't clear at all. I look down....forgot to put on the rear defroster. Pop it on....a few minutes later....the dusting of snow is unaffected. I get home, I check on it. It looks to be broken up a bit, but no more than the top of the roof from the cabin getting warm. I touch the elements from the outside, they feel the same temp as the glass.

What are other people's experience? Are these just not very good rear defrosters? Does it take awhile to warm up?

Update: Just out of sheer curiosity, I just went outside, popped the rear defroster on for 5 minutes and waited. Zero heat to the elements. No noticeable defrosting.
 
Last edited:

mtdoak

Well-known member
Joined
Aug 1, 2017
Messages
220
Location
Allentown, PA
Tesla Owner
Model 3
Country
Country
#3
Welp, to follow up here. I haven't taken my car in for service at all (nearest SC is 2 hours away) and my defroster is working, although slow. I will definitely have them check the wiring when I go down for other issues eventually. I was actually going to hold up my tinting until this got fixed, but I'm going to go ahead now since it obviously isn't an issue with the window itself.

 

Technical48

Active member
Joined
Apr 29, 2018
Messages
111
Location
Oviedo, FL
Tesla Owner
Model 3
Country
Country
#5
Drove over to the coast to watch the SpaceX launch tonight and upon leaving for home afterward I noticed that the rear window was fogged. It's a humid night so no surprise there. I tapped the defroster icon and it turned red but the window never cleared. I suppose it could be the physical connection to the heat strips. I'll look tomorrow for the connectors. Otherwise I guess it's a trip to the service center.

Has anybody else experienced this? I received the car a week ago and so far it has been brilliant. This is literally the only flaw I've encountered.
 

Chris350

Active member
Joined
Aug 8, 2017
Messages
140
Location
Jupiter, FL
Tesla Owner
Model 3
Country
Country
#6
I believe I have the same issue....

I have noticed on 2 different occasions that turning this on hasn't cleared the back window at all...

VIN 258XX - Del Date 7/12/18
 

kappadon3

New Member
Joined
Jul 16, 2018
Messages
1
Location
Eastern NC
Tesla Owner
Model 3
Country
Country
#7
happened to me this morning in steamy eastern NC. I happen to be in the scheduling phase of a mobile servicer for the rear camera issue so i called to add this to their review. we will see.
 

Technical48

Active member
Joined
Apr 29, 2018
Messages
111
Location
Oviedo, FL
Tesla Owner
Model 3
Country
Country
#8
Ah, two mornings ago I tried the defroster and it worked! I left the house earlier than normal, just before sunrise, so I wonder if there is some temperature limit above which it won't engage?

I have a service appointment next week to correct some other minor issues so I plan to ask about this.
 

Chris350

Active member
Joined
Aug 8, 2017
Messages
140
Location
Jupiter, FL
Tesla Owner
Model 3
Country
Country
#9
Apparently, there is a set temp degree.

According to SC, the rear defroster is not activate unless the temp outside is below 50 degrees....

It will show "turned on" if activated..... But does nothing if the outside temp is to high...

Major issue for us in FL.... the humitity here constantly fogs the rear window in the early mornings or late evenings...
 

Technical48

Active member
Joined
Apr 29, 2018
Messages
111
Location
Oviedo, FL
Tesla Owner
Model 3
Country
Country
#10
The service writer told that me the threshold temp is 75F, which matches my experience. IIRC the rear window defroster on my A8L drew ~300 watts, so it makes sense from an efficiency standpoint to limit its use.

But I agree, it's a bit annoying in Florida where the window can fog at 80F.
 

Tzoid

Active member
Joined
Jun 29, 2018
Messages
31
Location
Montreal QC
Tesla Owner
Model 3
Country
Country
#11
I don't understand why they would limit to 50F or 75F. Windows can fog up in a wide range of temps. I would think they would limit time ''on'' to less than the 15 minute default if outside temp is ''high''. Seems kinda dangerous. Do they do the same thing with the heated seats? That would suck 'cause I use the seat heaters on long drives to loosen up my back. If it affects the range thats on me.

And to save time for whoever is going to point this out to me; I know they are probably...no scratch that… They are the best seats ever created for an automobile and I won't be needing the heaters to loosen up my back. After a long drive it will seem like I had a combination Shiatzu, Swedish, Thai and Pregnancy massage.
 

Technical48

Active member
Joined
Apr 29, 2018
Messages
111
Location
Oviedo, FL
Tesla Owner
Model 3
Country
Country
#12
The seats seem to work regardless of the ambient temperature. I've used the seat heat while the ac is blasting at the same time.

This morning the rear window was fogged and the outside temp was 79F. Turning on the rear window defrost did not clear the rear window but the mirrors did clear. So it appears the heated mirrors will still function at above 75F.
 
Joined
Dec 31, 2017
Messages
23
Location
Sacramento, CA
Tesla Owner
Model 3
Country
Country
#13
I used it for the first couple times this week with morning temps in the 50-60s. It works but is slow to clear, much slower with dewdrops than with light condensation.
 

mbixby

New Member
Joined
Apr 9, 2016
Messages
4
Location
Miami, FL
Tesla Owner
Model 3
Country
Country
#14
I live in South FL and had the same issue two nights ago. My Model 3 was outside in the rain about 80F and rear window fogged up. Turned on the rear defroster for the 25-minute drive home and it never cleared even a little bit. I searched here and found others with a similar problem in FL I also have a Prius and in similar conditions that rear window cleared completely in about 4 - 5 minutes using the rear window defroster.
 

mbixby

New Member
Joined
Apr 9, 2016
Messages
4
Location
Miami, FL
Tesla Owner
Model 3
Country
Country
#19
Here's the response I received from a Tesla Service Advisor...

"I am in receipt of your concern regarding the rear defroster not functioning. You are correct in that it does begin to operate only after hitting a 75-degree threshold. Currently, Tesla is creating the firmware to be able to increase that threshold and solve this concern you have. I can fully understand how this is an inconvenience as I too need to turn on my rear defrost particularly in the morning to clear my back window. However, please know we are working toward a solution."
 

slotti

Active member
Joined
May 29, 2018
Messages
192
Location
Los Angeles
Tesla Owner
Model 3
Country
Country
#20
I can confirm the 75. SoCal here, and a couple weeks ago I thought it was broken. Fogged up rear but it was around 80 in the morning. Last couple days temps dropped around 70 in the am, and it was working. Weirdest thing ever.