Clean the weather-strips and the contact surfaces with cleaning solvent.

1. Apply powder or chalk in an unbroken line to the contact surface of the weather-strip surrounding the perimeter of the suspected areas. Ensure that the areas are free of chalk or powder.
2. Completely close the panel without slamming the panel. Completely closing the panel presses the weather-strip firmly against the mating surface.
3. Inspect the applied line on the weather-strip. The applied line is marred where contact is good. A corresponding imprint is on the mating surfaces.
4. Gaps or irregularities in the powder or the chalk line on the mating surfaces indicate the areas with a faulty seal.