To dry out housing I removed both bulbs and let a vacuum cleaner hose set in one or the other holes for bulb and let it pull air thru to dry out. The housing may need to be resealed.
I have a 2005 Toyota 4Runner and some of the wheel coating had come loose and a hole had rusted thru about where one of the mounts for the 3rd row seating is at. I found it by accident while looking up under the wheel well seeing a slight bulge and then poking it with my finger. The 4Runner has...