What's This Do?

Does that window come out, removable? Maybe it has something to do with holding in the window?

Rain deflection cap, the idea behind them is they're used to deflect rain away from the leading edge of the seam or area beneath so that there's less chance of water infiltration.

In this case, the idea is to deflect the rain/air flow coming over the cab and down the front of the camper into the gap between the truck bed and the cab so that it has less chance of puddling up between the front of the truck bed and the camper, as rain water in that area is being more forcibly driven that spray washing in via the slip stream along the sides.

I have one just above the window. Before putting it on, our step up to the bed would get wet when we were driving in heavy down pours.

No wet steps since.

With it below the window it would keep some of the water from running down the front wall and into the bed

My Lance 815 has it and it keeps the bed dry even during down pours. With my camper sitting back 1-1/2" from the bed, looks like the water would drip off the edge into the bed but it doesn't because of the wind. Just looked at mine and it does share the bottom window screws.

If the bottom of you camper is going to sit directly on a rubber mat, make sure it won't get hurt from sitting in water. If this is taken care of, then no issue leaving it off.

I haven't actually had this camper on the truck yet, so maybe I'll hold off reinstalling that piece until I see how it sits. I was reading the other thread about the cab-to-camper seal around the window and @kayteg got me thinking about fabricating something with a couple of pool noodles.

It isn't needed- it is just a diverter. Ours is narrow, pretty ineffective as campers rubber bumpers hold camper back enough water running off hits top of bed rail & can still run into bed. If you have room it doesnt have to go behind window and could be lowered.

Many campers don't have this. I know mine doesn't.

jdc1 wrote:
Keeps leaves out of the bed and diverts water?

Gets my vote. Seen rubber flaps there, too.

Keeps leaves out of the bed and diverts water?