I have a 2011 F150 Ecoboost and i keep having the problem of a saturated passenger floor carpet. I start to smell a musty and mildew smell and that is how i know that it is wet again. Each time i have to pull up the carpet and dry it out to prevent mildew from growing and making the cab of the truck stink.

The first time i pulled up the carpet i found the tape covering one of the drain holes had come off. I thought this has been the problem so i got aluminum tape and sealed that hole. But the wet carpet has come back. I have since continued to read about what the cause of this could be. I had read that there could be a clogged A/C drain and water from the condensation is dumping inside the cab on the passenger side or leaking back through the firewall. Does this sound feasible?

If so how do i clear the drain so it drains like it is supposed to. I have read of installing a 90 degree elbow extension to get the drain farther from the firewall and to ensure it drains down. I have climbed in under and around the engine and i have been unable to find where the A/C drain comes through the firewall and into the engine compartment.

Can anyone offer any solutions or help? Does this happen to anyone else?

 

I had a similar issue, turned out to be the third break light was leaking and water would run down into the wire channel on the passenger side door sill...

 

^^ yep