Camper shell not sealing

We just moved out in the country and I noticed I'm getting a lot of dirt in there. I don't mind washing it and it doesnt brother me that much cause all I have back there is trash most the time but I want to put a Truck Vault in there or something similar so I was wondering if it has happened to anyone else and how they fixed or if you can't.

 

Where is it coming in? Around the tailgate, or from the sides, or where, if you can tell?

 

I can't really tell honestly I checked all my windows so it has to be. Maybe has nothing to do with camper shell might be the tailgate.

 

Have someone get underneath your truck with a bright light while you climb in the back and look for light leaks. Not sure which year your truck is but they leak dust around the cubbies/storage compartments, between the pieces of the composite bed and the biggy- around the tailgate. Also check to make sure that your rear window seals, especially in the corners near between the tailgate, shell and shell's rear window. I pulled my cubbies and put thin weatherstripping around them, taped the seams in the bed and added a tailgate seal. It helps a lot but it still leaks some.

 

It will come in at the bottom of the tailgate between the tailgate and bed floor. It will also come on along the sides of the tailgate where the latches are.

 

Spray around it with a hose hit the Windows and seams with light-medium pressure