I've been monitoring water intrusion issues for the past few weeks on my 03 HD F150.
Per the suggestions of others I installed the AC drain tube fix a few weeks ago to solve an issue with water on my passenger floorboard. During this process I've tested/eliminated the sunroof drain as the source of any leaks.
Today after driving and having the truck sit in heavy rain all day I noticed a lot of water inside the passenger door sills/channel. This is the channel where the wires run through that you can see when you remove the uppermost door sill.
Judging by the condition of the door sill I can tell this has been going on a long time. I cannot tell if the water is coming from the front, middle, rear or underside of the truck.
Any suggestions on what might be the issue?
I'll experiment this weekend with a hose, but thought I'd toss this around on here for suggestions.
Here are some pics of the nasty door sills/channel: