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Rear window defroster buzzing

Daryl Casey
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Daryl Casey Enthusiast

Daryl Casey

Posted
Posted

2020 Sierra SLT

 

This morning I noticed a buzzing noise coming from the rear of the cab. The sound came from the right bottom of the rear window. The buzzing stops when I turned the rear defroster off. Turned the rear defroster back on, the buzzing started again.

 

Has anyone else had, or noticed, this problem? I tried to find a connecter to see if it was loose but couldn't find it.  I don't think it's affected the performance of the defroster, at least not yet. I figure it'll require a trip to my dealership's service department, which I'm not a huge fan of. 

 

Thanks for your time,

DC

 

 

Daryl Casey Enthusiast

Daryl Casey

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24 minutes ago, redwngr said:

I'd be getting it looked at, and I'd avoid using it until after. 

 

 

absolutely.

 

I have disabled the defroster from automatically coming on with remote start and also made an appointment with the local dealership.

S Schultz New Member

S Schultz

Posted
Posted

Would love to know what you find out.  My 2020 RST just just started doing this same thing three days ago.  Same spot too - passenger side right above the rear seat.  Currently have 7000 miles on the truck.  I have only noticed it in the morning when the temp has been about 35 degrees.  Doesn't seem to be doing it later in the day.  No idea if temp has anything to do with it.   

 

If you get yours fixed soon, can you let me know what was found?  I'll get mine in at some point, but it's always a hassle to take it to the dealer!

 

Thanks! 

 

 

Abiker21 Enthusiast

Abiker21

Posted
Posted
On 1/25/2021 at 11:24 AM, Daryl Casey said:

absolutely.

 

I have disabled the defroster from automatically coming on with remote start and also made an appointment with the local dealership.

The buzzing is electricity arcing. Luckily it will be under warranty for you. There is a recall but it only covers vehicles in certain cold weather areas. Canada made GM recall all trucks with the sliding rear windows with defrost. 

  • Like 1
redwngr Senior Enthusiast

redwngr

Posted
Posted
On 1/29/2021 at 11:33 PM, S Schultz said:

Would love to know what you find out.  My 2020 RST just just started doing this same thing three days ago.  Same spot too - passenger side right above the rear seat.  Currently have 7000 miles on the truck.  I have only noticed it in the morning when the temp has been about 35 degrees.  Doesn't seem to be doing it later in the day.  No idea if temp has anything to do with it.   

 

If you get yours fixed soon, can you let me know what was found?  I'll get mine in at some point, but it's always a hassle to take it to the dealer!

 

Thanks! 

 

 

If it's arcing and starts a fire, that will be alot more hassle than taking it in to get repaired....

Abiker21 Enthusiast

Abiker21

Posted
Posted
13 hours ago, redwngr said:

If it's arcing and starts a fire, that will be alot more hassle than taking it in to get repaired....

The arcing can produce a localized heat source and make the window explode. I have video of mine smoking before I pulled the fuse and submitted it to the .gov. They won't reply unless it becomes a recall. 

  • Like 1
DBCasey851 Enthusiast

DBCasey851

Posted
Posted
On 1/29/2021 at 11:33 PM, S Schultz said:

Would love to know what you find out.  My 2020 RST just just started doing this same thing three days ago.  Same spot too - passenger side right above the rear seat.  Currently have 7000 miles on the truck.  I have only noticed it in the morning when the temp has been about 35 degrees.  Doesn't seem to be doing it later in the day.  No idea if temp has anything to do with it.   

 

If you get yours fixed soon, can you let me know what was found?  I'll get mine in at some point, but it's always a hassle to take it to the dealer!

 

Thanks! 

 

 

Will do

Daryl Casey Enthusiast

Daryl Casey

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Posted

My dealerships service dept is very backlogged due to a COVID outbreak. Not sure when I'll be able to get my truck in for this issue, but please share what you find out with us here!

S Schultz New Member

S Schultz

Posted
Posted
7 hours ago, Daryl Casey said:

My dealerships service dept is very backlogged due to a COVID outbreak. Not sure when I'll be able to get my truck in for this issue, but please share what you find out with us here!

Well, my dealer can't find anything wrong.  My defroster was buzzing/arcing real bad on Saturday.  That afternoon, I happened to open the rear sliding window.  The problem has not happened again since doing that.  Have you dried cycling your window by chance?  Not even sure that's what caused it, but I had a feeling that's what the dealer would say when I dropped it off.  They couldn't duplicate the problem, and could not locate any service bulletins related to it.  Hopefully it doesn't happen again, but it's documented if it does.  Good luck with yours.

Daryl Casey Enthusiast

Daryl Casey

Posted
  • Author
Posted

I'll definitely give that a try. We've got an ice storm headed our way and the rear defroster would be nice to have! Thanks for the update.

 

  • 4 weeks later...
Bob E New Member

Bob E

Posted
Posted

I had this happen to my 20 RST.  I noticed there was a small leak and there was water coming off the track for the sliding window and running down the glass across the wires.  The wires were really hot.  I assumed it was the water sizzling on the wires because it only did it some of the time.  Dealer took it in and replaced the window.  Just got it back today so i'm hoping that solved it.

 

  • 4 weeks later...
Ed/2020RST Enthusiast

Ed/2020RST

Posted
Posted
On 1/31/2021 at 12:39 PM, Abiker21 said:

The buzzing is electricity arcing. Luckily it will be under warranty for you. There is a recall but it only covers vehicles in certain cold weather areas. Canada made GM recall all trucks with the sliding rear windows with defrost. 

I believe you are 100% correct. There seems to be a conductivity issue. I bet if you look closely at the area the buzzing is coming from a small arc can be seen at night and maybe even a small burnt spot!!!

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