how to disable rear defrost

[CarlosV]

I am afraid of bursting my rear window. Is there an easy way to temporary disable rear defrost (never use it, but accidentally gets turn on when putting thing in cup holders w/o me notice etc). The fuse(#15) in the engine bay for this involve other systems (multiport fuel injection). 2003 V6. Thanks

 

[AuSeeker]

I am afraid of bursting my rear window. Is there an easy way to temporary disable rear defrost (never use it, but accidentally gets turn on when putting thing in cup holders w/o me notice etc). The fuse(#15) in the engine bay for this involve other systems (multiport fuel injection). 2003 V6. Thanks

Remove the interior hatch panel and then unplug the electrical connector on the window and secure it out of the way of any moving parts.

 

[CarlosV]

thanks a lot once again Auseeker

 

[montijo505]

thanks a lot once again Auseeker

Alternately, break rear window with a bat. Not a problem if there is no glass to explode!


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[CarlosV]

brilliant! You should go to rest after this one

 

[montijo505]

brilliant! You should go to rest after this one

Lol enjoy your weekend!

Seriously though I never use that defrost button at all out of fear. I should unplug it myself.


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[SurferUK]

What's all this about exploding rear windows?

 

[Bluesky 07]

What's all this about exploding rear windows?

The apparent cause IIRC is unequal heating of the rear glass in defrost mode due to deterioration or breakage of the filament. So part of the glass heats up & expands slightly but the rest doesn’t. Under certain conditions, this leads to unexpected shattering of the rear glass.

 

[montijo505]

What's all this about exploding rear windows?

Several members over the years have reported their rear sliding glass exploding. Always in cold weather when they try to use the rear window defrost button.


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[SurferUK]

Several members over the years have reported their rear sliding glass exploding. Always in cold weather when they try to use the rear window defrost button.


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The apparent cause IIRC is unequal heating of the rear glass in defrost mode due to deterioration or breakage of the filament. So part of the glass heats up & expands slightly but the rest doesn’t. Under certain conditions, this leads to unexpected shattering of the rear glass.

Thanks for that - I don't think I would find that glass for sale here anywhere so I will leave that button alone!

 

[AuSeeker]

What's all this about exploding rear windows?

The apparent cause IIRC is unequal heating of the rear glass in defrost mode due to deterioration or breakage of the filament. So part of the glass heats up & expands slightly but the rest doesn’t. Under certain conditions, this leads to unexpected shattering of the rear glass.

Several members over the years have reported their rear sliding glass exploding. Always in cold weather when they try to use the rear window defrost button.


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I'm pretty sure I read the reason the glass was breaking was the electrical connection area itself was overheating and thus heating that corner of the glass causing uneven expansion which breaks the tempered glass.

Also here's a link to the Toyota "Extended Warranty" Technical Service Bulletin explaining the coverage, condition/inspection, etc. and it states that the condition can be identified by broken glass and discoloration surrounding the defroster electrical connector, there are photos as well.

https://static.nhtsa.gov/odi/tsbs/2017/MC-10131801-9999.pdf

 

[montijo505]

I'm pretty sure I read the reason the glass was breaking was the electrical connection area itself was overheating and thus heating that corner of the glass causing uneven expansion which breaks the tempered glass.

Also here's a link to the Toyota "Extended Warranty" Technical Service Bulletin explaining the coverage, condition/inspection, etc. and it states that the condition can be identified by broken glass and discoloration surrounding the defroster electrical connector, there are photos as well.

https://static.nhtsa.gov/odi/tsbs/2017/MC-10131801-9999.pdf

The takeaway here is, DO NOT use the defroster. Don't be lazy and scrape the rear window before your drive.

 

[MikeinNH67]

I wonder how often this actually happens percentage wise. I use mine often in the winter but always shut it off as soon as it is cleared, I don't let it stay on. No issues and it's an old truck.

 

[Sigma]

You can probably unplug the switch in the dash, or, if you don't roll down the rear window just roll it down ever so slightly. That will disable the rear defroster as well as the wiper and side view mirror heaters.

 

[TheUltimateBohab]

The apparent cause IIRC is unequal heating of the rear glass in defrost mode due to deterioration or breakage of the filament. So part of the glass heats up & expands slightly but the rest doesn’t. Under certain conditions, this leads to unexpected shattering of the rear glass.

Holy Crap I never heard of this... it makes sense... I always use my rear defrost and some winter days here get 40-50 below... probably literally shit if i was on the way to work and rear window shattered without warning... man that kind of sucks! I'm pretty sure that same button also powers the side mirror defrost.... right unplug at rear door not switch...

 

[AuSeeker]

Holy Crap I never heard of this... it makes sense... I always use my rear defrost and some winter days here get 40-50 below... probably literally shit if i was on the way to work and rear window shattered without warning... man that kind of sucks! I'm pretty sure that same button also powers the side mirror defrost.... right unplug at rear door not switch...

I'd say it would scare the crap out of you, from reports of those that have shattered it sorta sounds like a gunshot!!

And yes the same switch does the mirrors.

 

[cwilliams563]

I’ve heard about the spontaneous exploding rear window but never heard what caused it. I’ve used mine a few times, guess I’ve been lucky. I’ll have to try and avoid it.

Reminds me of the Tartan Prancer (equivalent of an Albanian Hyundai) from the 2015 movie Vacation, pretty funny. 2015 vacation movie car glass breaks clip - Bing video

 

[BackOff]

I am afraid of bursting my rear window. Is there an easy way to temporary disable rear defrost (never use it, but accidentally gets turn on when putting thing in cup holders w/o me notice etc). The fuse(#15) in the engine bay for this involve other systems (multiport fuel injection). 2003 V6. Thanks

You can in fact just pull the fuse, it is just the "defog" , pop the hood, open the fuse box just behind the battery. The defog is next to the fuel pump and unrelated... at least on this 2004 v6.
Fuse layout is on backside of the fuse box cover.

Mine has been out for a bit now, tossed it in the glovebox in case i need a spare.

$430 for new glass.

 

[CarlosV]

You can in fact just pull the fuse, it is just the "defog" , pop the hood, open the fuse box just behind the battery. The defog is next to the fuel pump and unrelated... at least on this 2004 v6.
Fuse layout is on backside of the fuse box cover.

Mine has been out for a bit now, tossed it in the glovebox in case i need a spare.

$430 for new glass.

My owners manual says different, as posted #15 fuse involve multiport fuel injection. What is the # in the one you are saying? Thanks.

 

[BackOff]

My owners manual says different, as posted #15 fuse involve multiport fuel injection. What is the # in the one you are saying? Thanks.

?
Mine runs just fine without.

Maybe they are different south of the border?

...extra wires (red is not attached) were for an air compressor for the old Rancho9000 shocks.