Inner lower pillar hinge pocket - relief hatch?

[_Ogre]

pour a bucket of water in those slotted vents in between the wiper bezels to how much moisture gets in there

if you don't make a have drainage in that area your cab corners will rot out in less than a year

the reason for the rust in these areas of our cabs is that leaves, pine needles and road grime enter thru the cowl vent
over a period of time the junk in there builds up and creates a blockage, the blockage gets wet and rust ensues

take your kick panel vent off, remove the vent door, feel over the top of the vent door there is a lip, feel the over the top of the lip
you are touching 40 year old leaves