I hope that you used a couple of shims/washers between the module and frame on the new installation. As previous posts have pointed out, the back rots out because water gets trapped. Two washers is all that's needed to allow any water to easily drain.
"Never argue with an idiot; they'll only drag you down to their level, then beat you with experience"
2007 F150 STX Supercab (4.6 2V V8), Edge tuner, factory navigation, Mark VIII electric fan conversion with flex-o-lite controller.