Like many others, I have water in the interior of the Bonneville. It all is located on the floor of the left rear passenger. Searches for the source had come up with nothing. After reading the forum, it showed I needed to look at other sources of entry of the water.

We were on a trip 2 years ago, and the left front window froze halfway down. in the hotel parking lot I took off the door skin and somehow got the window to work, out it back together and never had a problem since.

A forum member posted how his front driver door caused a water leak. I had checked the front many times as the source, but never found anything. It rained two nights ago and the rear passenger floor was flooded, nothing else. I decided to pull the plastic floor trim at the drivers door, and under the trim was wet carpet that was not visible without pulling the trim. After pulling up the carpet I discovered a channel in the under body that was the "river channel" that took the water from the front drivers door and placed it in the rear left passenger floor, all without showing any signs of moisture on the front driver carpet.

Will be pulling the driver door in the next few weeks to see what damaged I likely caused two years ago in the hotel parking lot.

I found water in my rear passenger floor a couple weeks ago.
Next time I'll pull the front trim to check.
I hope you find an answer and share...

Good information to know, thanks for sharing.

My water leak turned out to be a plugged sunroof drain on one side and loose drain on the other side. If you don't find the source of the leak at the door, check the sunroof.