Wet mildew smell in truck and camera failure; possible rear window leak again after TSB repair?

[tjonesdfw]

Had the rear window leak TSB done on our '21 Sierra over a year ago after multiple camera module replacements and the dealer finally claiming water had been dripping on the modules and shorting them out.  When they originally did the window TSB, we had not seen evidence of water at the top of the window or on the headliner. Lately, the truck has a wet/mildew smell for a while after being out in the rain, and the driver side camera started acting up for the 7th or 8th time yesterday.  Is there an easy way to pull the rear seatbacks and leave it open for a while to see if we can find evidence of water intrusion.  Checked all the floorboards and felt as far under the rear seats as we could and didn't find moisture, but clearly something is getting in to smell like this.  

[TheGeek]

On my 2020, I was able to find the leak when I pulled the rear door trim off the floor in able to reach under the carpet.  You could have soaked your feet there was so much water in the floor pan.   

[2016 Sierra Owner]

On my 20 they did the TSB repair. The day I picked it up I noticed it was still leaking. I called the dealer back and they scheduled me to have the glass replaced. It was replaced by a glass company (not the dealer techs) and all was good. The new window was an updated model to. It had a different part number than the old one. I traded it last year and a few days before that I think there was water around the top of the frame again.