Too ironic!!! My truck has been sitting for 3 months. I was working on it yesterday and noticed that the passenger door sill had water in it. I assumed it was the door seal. In retrospect I have notices my passenger floor seemed damp and behind the passenger seat also was damp. I just thought it was the slider window. Mine is a 1988 K1500 so maybe it's a body design thing for water run off?
