Originally Posted by srderby
+1 on the fantastic fan. Quitter and works much better. Can't remember the name of it but there is a law passed that says they cannot simply void warranty. They would have to show that the specific mod that you did caused the problem.if it's done correctly you have nothing to worry about.
I think you're referring to the Magnuson–Moss Warranty Act. It's actually pretty old at this point. The main idea that people often quote about this is that the manufacturer can't require you to use "branded" parts. They also can't refuse a warranty just because you made a modification to their product, and responsibility is on them to prove that what you did caused the problem.
In the case of a trailer, if someone installed a fan, and then had leaks that caused damage, if the warrantor can prove that by installing the fan, you directly
caused the leak, then they can refuse warranty repairs.
However, if the leak was at the other end of the trailer, it would be hard for them to prove that the work you did caused the problem. They also can't void the whole warranty just because you worked on one part of it. Again, if the leak was at another spot in the roof, unless they can prove that you caused damage while up there, then they can't deny the warranty. Also, they can't void the warranty on the water heater, for instance, because you added a fan.
Of course for many consumers, it's difficult for you to dispute what they may claim. "Well, it looks like the roof may have been scraped by a branch at one point, see these microscopic marks? Yeah, this isn't covered."