Power Window problems of the 2006 Toyota Sequoia

Pushed switch for power rear tailgate window, window assembly broke and window fell down into door. Upon examination, all components - regulator assembly and all connecting parts were severely corroded which led to failure. Less than 12 months later, rear tailgate outside handle broke; again under examination the entire interior latch assembly was severely corroded which caused failure. This in my opinion is a design or assembly defect. Water is not supposed to be leaking into the interior of the tailgate. From the extent of corrosion, this condition had been occurring for many years - most likely in my opinion immediately from the time that we acquired the vehicle new. The failure, while caused from a defect from the beginning of vehicle life, manifested itself after the vehicle warranty period and Toyota is refusing to address. From some online research, I have found this to be a common problem.