1999 Mercury Cougar body & structure problems

1999 mercury cougar leaks water into hatch area directly onto the interior exposed electrical wiring and connections for tail lights and hatch release. Dealership cannot determine source of leak and therefore cannot repair. Mercury will not release blueprints of sheet metal layout to help in determining where water leak might be originating. Neither did mercury cover diagnosis and will not cover repair even if problem source was identified.

I have always had my car washed and rust proofed during the winter ever 2 weeks. Last december the paint under the bottom of both the drivers and passenger doors started having the paint bubble up on both rocker panels. It started bubbling up then curling and the pain started coming off. Ive seen many other cougars with this same problem and feel it is due to a defect in the paint that was used or something missing from the paint job that was done