water intrusion

Took the Raptor in yesterday for warranty and recall work since the drivers side tail light has excessive condensation to the point water trickles down inside. The Blind Spot sensor screw tabs are broken so the sensors don't seal against the gasket allowing water penetration. Ford Service took...

I wonder if expanding foam would work under the bed rail caps and in those two large cavities in the top corners of the front of the bed? Maybe that would help with water intrusion. Not sure how chemicals in the foam would affect painted metal.