Bad tail light on Four Winds 28Z
I, too, needed to replace 4 bulbs after few months of use. The bulb was not blew but it was damaged by water intrusion (rusted contacts) into the tail-light assembly due to the cheap foam gasket. Upon removing the assembly, I also discovered some plywood decay and it was soaked. I dried the area, checked for delamination of the area, then sealed the tail-light with generous bead of clear silicone caulk. I'm also replacing the screws with stainless one. "Shoddy workmanship with apparently no quality control."
I think that Thor should a recall of these RV and replace the defective tail lights Command 003-30.