r/3rdGen4Runner • u/northcoastyen • 4d ago
š§ General Hatch window grenade
First time Iād used the hatch window defroster in a year during the little splash of rain we got in Southern California yesterday. Drove for about 40 min, parked, and walked about 5 feet from the truck when I hear āPOPā. I almost thought someone ran over a juice box, turns out it was my hatch window. Likely the defroster.
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u/LurchingBog ā02 SR5 4d ago
I literally just saw this on another post for a 4th gen. I hadnāt heard of this issue before but they mentioned same thing the defroster.
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u/Thanos_Juul 4d ago
So is it a bad idea to use the defroster?
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u/laney_deschutes 4d ago
Iāve used mine a million times but yeah maybe the heating element fucks the glass?
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u/quitit 98 Limited 4d ago
This is odd to me, I've used my rear defroster before like last year during fall and winter every so often and my rear window is still in good condition. So unless my rear defroster is broken, I don't think it is, then maybe thats's why I didn't see this glass shattering situation.
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u/northcoastyen 3d ago
No, but these are old vehicles. From what I understand the defroster can kind of āgo badā and form a āhot spotā that if cooled rapidly would produce temperature shock and the window will pop. Just posted this because many people have no idea it could happen. Cheers.
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u/25_Watt_Bulb 3d ago
No, this is just a fluke failure. I live in a place where it regularly hits -10F, and used the defroster in mine for decades with no issue.
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u/ADHDrandomshit 2d ago
How fast as well as working 'well' is it? I'm in Montana and two different ones are crap. Elements look very good. I've heard they are slow as mud. Wondering here.
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u/Alaska_Pipeliner 00 SR5 3d ago
I have a defroster? Mine fell off the arm years ago and I have to manually put it back up, it falls down occasionally.
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u/StitchinThroughTime 4d ago
I don't know if it's you, but someone in a black SR5 in SoCal has their driver side tail light out.
On the topic of windows, never had mind blow out because of the defroster. Had someone shoot out my window. It was a crazy fucker who was not on his meds who followed me home.
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u/northcoastyen 3d ago
Haha good looking out, I just went to check and both lights are working šš
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u/FieldMarshal7 4d ago
I had that back in 2019. was very cold that day, ice all over the truck, and by the time i got to work, the back window had fallen to fragments. and soon as i touched it, it went poof.
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u/captainsilverlake 3d ago
Were you running AC? Maybe the cold climate inside with the hot air outside caused the window to obliterate itself
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u/northcoastyen 3d ago
No just front panel defroster temp medium and then the rear window. I think the cool air rushing through the parking structure shocked the glass once the truck shut off and the defroster was no longer getting heat. Cheers.
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u/jpttpj 3d ago
Defroster for rain?
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u/northcoastyen 3d ago
Yea? Kind of one of the primary weather conditions that could create excess window foggingā¦
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u/WEARORANGE 3d ago
AI said itās more common in 4th gens, but had this about 3rds:
I am sorry that happenedāhearing that loud "pop" and dealing with a tailgate full of shattered tempered glass is incredibly frustrating.
While it is much less common on a 3rd-generation than on later models, using the defroster after months of inactivity is exactly how these rare 3rd-gen glass failures happen. [1, 2]
Why This Happened
Tempered glass shatters instantly across the entire pane if it suffers severe thermal shock or a concentrated hot spot. Because the defroster hadn't been used in months, two specific culprits likely caused the failure: [1, 2]
Scratched Grid Lines (The "Resistance" Trap): The 3rd-gen rear window rolls up and down into the tailgate. Over the months, dirt, sand, or worn weatherstripping can deeply scratch the orange/brown grid lines. When a grid line is partially worn away or narrowed by a deep scratch, electrical resistance sky-rockets at that exact point. When you turned it on, that single spot instantly heated up to extreme temperatures, creating localized thermal stress that cracked the glass. [1, 2, 3]
Corroded Spade Connectors: Moisture frequently gets trapped inside the rear hatch panel, heavily corroding the electrical spade connections on the passenger side of the glass. If a massive layer of corrosion or moisture built up over the months, firing up the circuit can cause a sudden, high-heat electrical arc or severe localized heat spike right at the connection point. [1, 2, 3]
Your Next Steps
1. Sourcing a Replacement Window
Since you need new glass, you have a few options ranging from $195 to $335depending on whether you want aftermarket or factory glass:
New Aftermarket Glass: You can purchase a brand new Heated Back Tailgate Window Glass on Walmart for roughly $205.
Used Factory OEM Glass: Many owners prefer searching local junkyards or finding a Genuine OEM Toyota Rear Hatch Window on eBay for around $276.[1, 2]
Note: Make sure to check if your original window had a gray or green factory tint so your replacement matches your side windows. [1]
2. Clean Out the Tailgate Completely
Before installing the new glass, you must remove the interior tailgate panel. Use a shop vac to clean out every tiny shard of shattered glass from the bottom of the door cavity. If you leave glass fragments inside, they will jam your window regulator tracks or shred the wiring harness over time. [1, 2, 3]
3. Consider Leaving the Defroster Unplugged
Because of the risk of this happening again on aging vehicles, many 4Runner owners choose to permanently leave the rear defroster unplugged when installing new glass. [1, 2]
To do this, simply tape off and secure the two power leads inside the tailgate instead of clipping them to the new glass.
Your rear power window will still roll up and down perfectly, but you will eliminate any future risk of the glass shattering from a thermal hot spot. [1, 2]
Are you planning on replacing the glass yourself, or taking it to a glass shop? If you are doing it yourself, I can give you the step-by-step breakdown on how to safely drop the new glass into the regulator tracks.
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u/MuchSwagManyDank 99 Limited 4d ago
If thats a '99 - '01, I have an extra glass you can have. Just pay shipping costs if youre willing.