Your fifth wheel is covered under the federal Magnuson-Moss Warranty Act. This basically states if the manufacture gives you a written warranty, they must live up to that warranty. If they are unable to correct the defect as stated in the warranty, they have to replace the product or refund the money. Your state's version of the lemon law only applies to motorized RV's under a certain weight. Since the actual warranty and all its legal written provisions is key to lemon law cases, you should consult a lawyer. If you win, the manufacture has to pay all your legal cost.