Rear Defrost Model Y

[Morpheus84]

Morning all! I just had a window issue with my Model Y and had some tech support over the phone. Whist fixing the issue they asked me to check on something to see it if was enabled ‘Enable Rear Defrost’. On my car it was not. The service tech told me a lot of new MYs left the factory with this disabled and told me to enable it. There have been a number of threads regarding the rear defrost so this might be the answer.

To get into service mode: Click on Software, then hold down your finger on the Model Y logo. Let go and then enter ‘service’ as the password. Then click on ‘Closures - Windows’ and you will see the enable rear defrost icon. If it has a green outline it’s enabled, if not click on it to activate.

 

[DaveW]

Bookmarked, thank you!

 

[mick4545]

Didn’t work for me, rear defrost still disabled. Clicking the software button started an update to 23.1 I’ll try again after it finishes.

 

[Morpheus84]

Didn’t work for me, rear defrost still disabled. Clicking the software button started an update to 23.1 I’ll try again after it finishes.

Yeah you need to get into Service mode first so try after that. Just hold your finger on the words ‘Model Y’ for 5 seconds and then let go and a password prompt pops up.

 

[mick4545]

I got into service mode ok, probably not following instructions correctly. Will try again later.

On the bottom of the service menu was a red line with the text “Speed Limited”

 

[mick4545]

Sorted. Its now counting down from 7800, whats that about?

 

[H43lio]

I just gave this a shot and I could follow the steps without much issue. There was one step where I needed to activate Gateway mode which seemed to go through OK and not I have 'Enable Rear Defrost' surrounded in green.

How do I check if this actually made a difference though? I've already had the icon for rear defrost in my HVAC settings, so does this mod I just did mean that that button actually does something now?

 

[H43lio]

Sorted. Its now counting down from 7800, whats that about?

I think that is how long the Gateway Unlock lasts for before you need to go through the unlock procedure again. I just exited service mode after making the change and rebooted the MCU (press and hold both steering wheel buttons for a few seconds).

 

[mick4545]

I just gave this a shot and I could follow the steps without much issue. There was one step where I needed to activate Gateway mode which seemed to go through OK and not I have 'Enable Rear Defrost' surrounded in green.

How do I check if this actually made a difference though? I've already had the icon for rear defrost in my HVAC settings, so does this mod I just did mean that that button actually does something now?

Pressing the defrost button now shows it as active for front and rear..

 

[mick4545]

I think that is how long the Gateway Unlock lasts for before you need to go through the unlock procedure again. I just exited service mode after making the change and rebooted the MCU (press and hold both steering wheel buttons for a few seconds).

Many thanks, every thing now in order.

 

[chwe]

Just went into service mode and mine said it wasn't enabled, so have turned it on.

The heating element in the rear window seems to be divided into a lower and upper section I put defrost on and the bottom section of the window heats up (I've no idea whether it was before I turned it on in service mode), however the top section doesn't seem to. Is this the same for everyone else?

 

[garym999]

Yes thanks for the link. Since I have had the car I have had random issues with the windows not closing properly. In this menu it said the passenger front was uncalibrated although I have had issue with them all. So I have run the calibration and see how we go. Also enabled rear defrost while I was there.

 

[Morpheus84]

Just went into service mode and mine said it wasn't enabled, so have turned it on.

The heating element in the rear window seems to be divided into a lower and upper section I put defrost on and the bottom section of the window heats up (I've no idea whether it was before I turned it on in service mode), however the top section doesn't seem to. Is this the same for everyone else?

That’s standard I think as the upper potion doesn’t obscure the view

 

[Morpheus84]

Yes thanks for the link. Since I have had the car I have had random issues with the windows not closing properly. In this menu it said the passenger front was uncalibrated although I have had issue with them all. So I have run the calibration and see how we go. Also enabled rear defrost while I was there.

I am having these window issues. Sometimes they close, sometimes half way and open. Sometimes one inch from the top and then back open. Sometimes the switch does nothing at all. I have an appt at the service centre after Xmas to investigate. I have a feeling it’s a resistance issue and the motor is overheating when the switch isn’t working.

 

[garym999]

Regarding the windows I think there are a few issues at play here. The motors won’t be overheating but the current sensing is used to sense an obstruction. once sensed it will retract to prevent entrapments (fingers etc.). I think the stiffness of the glass (dual layer) and the twist of the body while driving will be the cause. One obvious software fix would be to turn down the sensitivity of the current sense but then when on the drive and your little ones get their fingers trapped…. You don’t want to finish that thought. So it’s a compromise. I have had issues occasionally with a lot of cars over the years and just holding the button up after a bounce until its fullly closed resulted in a recalibration.

 

[MrBadger]

The window calibration instructions are in the manual. No need to resort to service mode.

A recent software update changed the sensitivity of window object detect and this time of year when possible freeze, windows self adjusting on door close to leave a small gap at top which is by design.

 

[Morpheus84]

Regarding the windows I think there are a few issues at play here. The motors won’t be overheating but the current sensing is used to sense an obstruction. once sensed it will retract to prevent entrapments (fingers etc.). I think the stiffness of the glass (dual layer) and the twist of the body while driving will be the cause. One obvious software fix would be to turn down the sensitivity of the current sense but then when on the drive and your little ones get their fingers trapped…. You don’t want to finish that thought. So it’s a compromise. I have had issues occasionally with a lot of cars over the years and just holding the button up after a bounce until its fullly closed resulted in a recalibration.

Interesting you mention about driving, my window issues are much worse when driving.

 

[Pandinium]

Interesting you mention about driving, my window issues are much worse when driving.

I had to pull over today stop the car and go check, as I heard an air gap and thought it was the door. But it was the passenger window not going all the way up, but once I stoped it seems to closed normally

 

[Morpheus84]

I had to pull over today stop the car and go check, as I heard an air gap and thought it was the door. But it was the passenger window not going all the way up, but once I stoped it seems to closed normally

Definitely a design flaw somewhere. I just can’t trust the auto close walk away feature but I’ll see what the service appt throws up.

 

[ThunderBay3Y]

After reading this, I am in Northern Ontario Canada where it is currently about -20C (-4F) and have noticed my rear defroster certainly doesnt work as well as it did on my ICE vehicles I checked the service settings and yes the Enable Rear Defrost was not turned on. I turned it on. Interesting though I went into my M3LR and it was also not on. I've turned it on in both cars and really haven't noticed any sort of difference. Anybody know what that setting actually does?

The defrost always worked i guess but it just seemed to be very slow to defrost a window - you didnt get the lines in the window like you do within minutes on my previous ICE.