Search the forum, there have been a ton of them replaced.

 

It appears to be an aluminum base screwed flat to a steel frame. That is not a good combination, add in that it sits above the spare and probably doesn't dry out real quick. Add in winter, salt, snow, slush and dirt.
How many miles and what year? I do not know that these modules were redesigned until after '08. The replacement is not the same. The new ones do not screw flush to the frame. There are standoffs to leave an air gap. Helps with drying i guess. Who would have ever thought of that? Miles, well I can't say. The question is, do I want to change it before it goes bad, or wait until I can't get home. And what does yours look like?

 

Mine died after 4 winters and 14.000
Miles. I had to wait 5 weeks for the new one because i live in germany.

 

if yours still works pull it and check it out if its not to badly corroded install spacers so it does'nt contact the frame it will last longer. i pulled mine and it was almost corroded thru so i replaced it. the new one comes with spacers.

 

What year is your truck and how many miles on it?