This weekend I was re routing my wires for my stereo to my back seat. While taking everything apart I pulled up the carpet and the back seat behind the driver's side, the padding was soaking wet. I looked around and everywhere else was dry in the truck except this area. The carpet had a rubber bottom so it couldn't of leak from there. They were no obvious holes, but there were two plastic plugs on the bottom. Could those be the problem? The wet spot took up the whole back side of the cab. What should I do to keep water from getting in?