I was detailing today the inside of the car and while taking a break I noticed the plastic cover on the door jamb (got a pic with it) and made me wonder why that hole exists there.If you go inside the car you already have plenty of holes to get inside the rear quarter panel so that hole there makes no sense plus it sits outside the weatherstrip so i guess if you preassure wash the car you can get water inside the body.

can anyone explain the design behind it?Its not important or anything but cant find the logical answer ...oh and yes I did a

 

The door vents are part of the flow through ventilation system when using the heater, A/C and shutting the doors. They relieve the pressure inside the vehicle.

 

That makes sense
They looks like a intake for air thou .

 

They are also how your access the back side of door striker bolt mounting plate for adjusting your door pin striker.

 

The vents also have rubber flaps on the inside; I found this out when I took them out to repaint them. They should keep water out for normal cleaning.

 

It is an intake. Cabin air flows into that vent and gets vented out of the car.