Rear window leak

OhioSpartan · January 7, 2020

Add another one in Cleveland, Ohio. 7/19 build date in Ft Wayne.

Purchased 12/7/2019.

2019 Sierra Denali Ultimate 4WD

The day I bought it the rear window started rattling. 4 days later had it in the shop for them to id the source. They claimed the rear window needed to be replaced. Order a rear window and took it back in on the 20th. That afternoon Service Director called to tell me the window guy said the window was fine, the rattle was the pressure vents. They showed me the vents with the seats and everything removed. Service Director joked I was lucky it wasn't leaking as that shorts out the ECU which cause the screens to go black. They ordered parts but by 23rd they hadn't arrived. I had a trifold tonneau cover ordered that they installed on the 24th. I needed the truck to go skiing so I picked it up on the 24th and wedged towels between the rear headrests and rear window to stop the rattle. Truck sat in my garage until the 28th when we drove to Detroit. We were having issues with the SD Nav card error so I googled it and fixed it after reinstalling it 3 time that night. It sat in the driveway overnight in a heavy rain. Packed it up and headed to the gas station around noon on the 29th when the displays up front blacked out. After restarting the truck 4-5 times things stopped going haywire ( touchscreen wouldn't work, delayed touch response, blinking scree, blackout, dropping bluetooth, etc). At this point I was pissed.

2 hours later on the way to Traverse City (still in light rain) my daughter notices water on her shoulder in the rear driver seat. My son check his side and water there too. I blamed condensation and turned on the defrosters but there was a steady line of water coming in the rear driver's side. Droplets were on the passenger side sliding window frame.

I had my daughter put a small rag in the corner to soak up any water. It rained on an off for 2.5 hours and every time it rained, water entered. And I found this forum... For those 2.5 hours I was on here trolling, getting angrier and angrier.

I called the dealership the next day and they offered to get me in right away to replace the window and the ECU. They had seen 4 of these before. I was 6 hours ways skiing and unable to get there until today, Jan 6th. I put a small tarp over the cab trying to limit water entry as there is no garage at the cabin.

Yesterday I decided to check the headliner for stains and saw 3 distinct rings. I called the service director and told him about the situation and wanted to meet with him and the dealership GM this morning at 8am. I also emailed the dealership GM and have not heard from him.

I arrived at 7:59 am this morning... no GM to be found but service director is great. I told him I wanted a new truck and this truck would never be able to prove to me there hasn't been more damage He had a glass and leak guy in to check it out. The front desk girl told me that even if they couldn't see the screen issues she was sure that water had started to corrode the unit.

At noon the service director called to tell me the leak guy saw my window frame was cracked in upper passenger side. They wanted to make sure it wasn't the 3rd brake light. They will be replacing the rear window, the ECU that is mounted back there, and they claimed they removed the stains today from the headliner and that the cardboard up there showed no water damage. He also said the GM was going to call me... no call yet.

I stopped by there at 5 pm ( I work 2 miles away from the dealership but 30 minutes from home) and sat down with the service director and the sales guy who sold me the truck. Service Director explained the fixes and I explained that while I am sure he can fix it, he can't be sure what else has been damaged. He told me he had been in touch with the GM rep and they wanted him to fix it. He also told me that GM would offer me 10,000 in GM Rewards.... equal to a $50 gift card! He was clearly embarrassed and I told him I would accept nothing less than a 10 yr/100k mile bumper to bumper extended warranty. If GM wants me to keep the truck I am assuming all the risk so they need to put skin in the game. He told me I had to contact GM customer care who would call him to confirm my story. He also told me the dealership GM and he had been discussing my situation so I told him I wanted to speak to the GM. I was told to email him to request a meeting.

During the conversation he told me he thinks the window frame cracked between the 20th and 28th. He says he would have noticed the headliner stains as they were all over it on the 20th. I am beginning to think that may be true, and this a frame flex issue that will cause recurring issues with these windows. Hence my demand for an extended warranty to cover it and any unknown water damage that will rear its ugly head later.

My next step is to talk to the dealership GM. I purchased an extended service contract for 5 yr/60k (non-GM) from them and I want a refund plus a GM extended warranty. I plan to ask for the GM rep's phone number to contact directly. I also plan to email execreferal as posted here to open a case. I will be emailing the VPs at GM as well (email posted on this site) and contacting the nice GM VP who sent me the thank you note that arrived while I was on my trip :). I have purchased 3 GM vehicles (2 Buick Enclaves and this truck) in the past 7 years and this has been a disaster.

Thank to you guys I kept my cool, have documented everything and have a method to try to recover my sanity. Today ends day 30 of truck ownership. Never owned one before... may never again.

Key message for everyone, make them replace the ECU that sits below the rear window. It is likely damaged and will fail if it has gotten wet.

Oh yeah, and my tailgate motor sounds like it's about squeal away. Also being checked. I will get to my 8 issues or 30 days out of service for lemon law one way or another...

Edited January 7, 2020 by OhioSpartan

OhioSpartan · January 7, 2020

Edited January 7, 2020 by OhioSpartan

Porterhouse · January 7, 2020

The ECU is in the rear?? Update on mine. They called and said they haven't found the source of the leak but already ordered me a new headliner. I find this odd but hopefully they're gonna fix it how I want it done.

OhioSpartan · January 7, 2020

Yes. According to the service team. I saw multiple modules mounted to the rear frame when they showed me the pressure equalization vents. They claim they have replaced a few of these due to the water window issue. I am sure there is more than one computer in the truck though. This one controls the displays in the instrument panel and the touchscreen apparently.

Edited January 7, 2020 by OhioSpartan

Porterhouse · January 7, 2020

Thank you definitely good information for when I pick mine up

Porterhouse · January 7, 2020

I can't wrap my mind around why they would put it there?? Seems like it's further away from the engine n gauges there. I'm gonna look under the rear of my rental tomorrow n see if I can locate it.

OhioSpartan · January 7, 2020

Both the service desk girl and the service director said so. He was pretty specific that they would have to replace it and reprogram it. He even mentioned the exact number of connections to plug in. It was oddly specific info to share which made it stand out to me. I will find out what part it is exactly when I talk to him Wednesday and post it here. I recall seeing at least 3-4 electronic modules mounted back there. Service desk girl even commented how it was stupid design.

Porterhouse · January 7, 2020

Thx for the tip. I appreciate it. Very helpful while mines being worked on with the leak with under 200 miles

ShamrockShooter · January 7, 2020

Someone posted this on the Facebook group. You can see the modules on the back wall. Also odd the seat backs come off without taking off the seat bases based on this picture. On the k2 trucks the seats were one piece.

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lapoolboy · January 7, 2020

12 hours ago, Porterhouse said:

I can't wrap my mind around why they would put it there??

They didn't. The ECM (engine control module) is in the engine compartment on the driver's side in front of and below the airbox.

ShamrockShooter · January 7, 2020

So apparently my new window is in already. So I have the option to install the seam sealer fix over top of the new window before they put the spoiler on as a "double" line of defense. Thoughts?

I think I'm leaning towards just the window as I would want to know if the frame cracks right away again. Versus having it crack and be covered by sealer only to leak again in a year when the sealer fails.

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Porterhouse · January 7, 2020

7 minutes ago, lapoolboy said:

They didn't. The ECM (engine control module) is in the engine compartment on the driver's side in front of and below the airbox.

What's the electrical boxes under the window power?

lapoolboy · January 7, 2020

2 minutes ago, Porterhouse said:

What's the electrical boxes under the window power?

Lots of things....they are body control modules..accessory power control, etc.

Porterhouse · January 7, 2020

2 minutes ago, lapoolboy said:

Lots of things....they are body control modules..accessory power control, etc.

So that still could be a mess if water got into them

magnum74 · January 7, 2020

I got hooked on reading through this entire thread and the fact that the problem has carried over into some 2020's makes me thing twice about dropping money on one of these new gen trucks in a year or two. No matter how much they test this stuff still happens. Leaky window is never acceptable no matter the price point of a vehicle.