What's at the bottom of my '03 doorliner?

[roegs]

There is a thin black plastic sheet that sticks below the door panel on all 4 doors of my '03 crew cab. It runs the whole length, and sticks below the panel just far enough (approx 1") to be sandwiched between the door itself and the door gasket on the body. The sheet on the pass side seems to be slipping out of the liner a little. Anyone know what these are for?

[thechevyhdman]

I think that they are their so the weatherstripping on the truck wont wear off the paint on the door(under the black plastic sheet) I think. Bill

[battmain]

There is a vapor barrier that protects the inner side of the door panel from the elements. It could stick below the panel if the fine assemblers were lazy on the day they built your truck. It could also be the plastic wrap that covered the door during shipping. One way to find out is to remove the door panel. (very easy to do.)

[GMC D-Max]

The black plastic piece is attached to the interior door panel. The '01-'02's have it, too. I'm assuming it's purpose is probably as Bill stated, along with preventing the lower seal from "glueing" itself to the door which could cause it to tear.

[JimWilson]

Those "fine assemblers" must have missed mine too, because all four doors have at least one inch of that stuff below the interior panel.