I've been chasing this #%^$%*&^ water leak in my trunk for a long time. I think I may have found the culprit. Its been leaking into the trunk at the farthest corners under the package shelf. I thought it was the rear glass. Today I tried a theory. opened up one of the rear doors (RR) and in the door jamb at the top, a moulding comes down from the roof, to about the middle of the jamb. This moulding is secured to the body by self-tapping screws. The backside of the moulding was supposed to have a gasket, gone now due to age. So I used a squirt bottle with water, into the top screw hole, and it came in the trunk in the exact spot where its been leaking.
Tomorrow or Wednesday I will do the repair. Probably seal around the holes with black RTV or butyl tape ( stuff they use to secure winshields) then water test.
Will update with results.

wow, i never woulda thought.

can you get any pics of this gasket you speak of?

I'll have to get my hands on a digital camera, give it a try.

That seems like an unlikely entry point for any real quantity of water, but let us know how it works out. There'* a lot of cars with that problem.

After dinner, I went out and popped open the trunk. We have had rain since I had the Bonne' washed on Sunday afternoon. After the last rain, I had pulled the trunk weatherstripping and added some rtv under it - along the front drivers' side corner.

Upon inspection tonight, there was still a light seepage past the seal and into the trunk. I could feel light moisture on the bottom of the trunk lip inside the seal. I will need to look again tomorrow - in good light. The corner also has a sheet metal weld. I think the rtv helped as a bandaid, because the trunk mat used to really soak up the water.

I looked at the door trim/gutter seals too. However, I didn't see where the water would get from there to the trunk. I'll look at that also and post a pic if needed.

Hey guys, I know this is a common problem with our year cars. I'm still working on it. The moulding inside the rear door jambs-you have to remove it, 3 screws and 3 screws on the other. You will see holes drilled from the factory in the 1/4 panel. Those screws are supposed to be sealed either with rtv or some sort of gasket material. I sealed one side with duct tape, and it rained last night, no water in trunk.
So today, I insulated the moulding with butyl tape, sort of like strip caulk also put some on the threads of the screws. Will probably water test tomorrow. Will try to find pics to help understand.
Be patient. I'll find it.